Flexible production of benzene and derivatives thereof via oligomerization of ethylene

ABSTRACT

Disclosed is oligomerization of ethylene to form 1-hexene in combination with aromatization of the 1-hexene formed by oligomerization, to form benzene.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a non-provisional patent application claiming thebenefit of, and priority to, U.S. Provisional Patent Application No.63/367,651, filed Jul. 5, 2022, which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

The present disclosure relates to the integration of systems andprocesses associated with steam cracking, oligomerization reactions, andaromatization reactions such that benzene can be produced viaoligomerization of ethylene.

BACKGROUND

Benzene, also known as benzol, mineral naphtha, phenyl hydride, andannulene, is an aromatic compound that is an important item of commerce.Benzene is found in crude oil, is a component of gasoline, and is awidely used industrial chemical including application in the manufactureof plastics, resins, synthetic fibers, rubber lubricants, dyes,detergents, drugs, pesticides, glues, adhesives, cleaning products, andpaint strippers. Conventional methods of benzene production that beginwith materials contained in crude oil are increasingly expensive due toincreasing demand for crude oil. Methods of producing benzene usingnatural gas as a starting material can provide a lower cost alternative.Thus, additional novel and improved systems and methods for benzeneproduction are desirable.

SUMMARY

Disclosed is a method comprising: contacting, in an oligomerizationreactor, ethylene and an oligomerization catalyst to yield anoligomerization reactor effluent comprising 1-hexene; recovering1-hexene from the oligomerization reactor effluent; and contacting, inan aromatization reactor, the 1-hexene recovered from theoligomerization reactor effluent with an aromatization catalyst to yieldan aromatization reactor effluent comprising benzene.

A system comprising: an oligomerization reactor configured to contactethylene with an oligomerization catalyst to yield an oligomerizationreactor effluent comprising 1-hexene; and an aromatization reactorconfigured to contact 1-hexene recovered from the oligomerizationreactor effluent with an aromatization catalyst to yield anaromatization reactor effluent comprising benzene.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic of an integrated converting system.

FIG. 2 illustrates a schematic of a cracking process.

FIG. 3 illustrates a schematic of an oligomerization process.

FIG. 4 illustrates a schematic of an aromatization process.

FIG. 5 illustrates a schematic of a derivatization process.

FIG. 6 illustrates a schematic of another integrated converting system.

FIG. 7 illustrates a schematic of another integrated converting system.

FIG. 8 illustrates a schematic of another integrated converting system.

FIG. 9 illustrates a schematic of another integrated converting system.

FIG. 10 illustrates a schematic of another integrated converting system.

FIG. 11 illustrates a schematic of another integrated converting system.

FIG. 12 illustrates a comparison of the price of ethylene with the priceof benzene.

FIG. 13 displays conversion for converting 1-hexene to benzene.

FIG. 14 displays selectivity for converting 1-hexene to benzene.

DETAILED DESCRIPTION I. Overview

It should be understood at the outset that although an illustrativeimplementation of one or more aspects are provided below, the disclosedsystems, processes, and/or methods can be implemented using any numberof techniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but can bemodified within the scope of the appended claims along with their fullscope of equivalents.

Disclosed herein are systems, processes, apparatuses and methods formulti-step chemical converting wherein several chemical transformationsare integrated into a single, continuous-flow system. The integratedconverting systems as well as the processes, apparatuses, and methodsassociated therewith, are generally related to continuous-flow systemswhich integrate converting C⁴⁻ hydrocarbons, such as hydrocarbonsderived from natural gas (e.g., ethane), into oligomer intermediates(e.g., 1-hexene), which are further converted into arenes (e.g.,benzene).

As disclosed herein, a method of utilizing an integrated convertingsystem generally comprises the steps of (a) cracking a hydrocarbonfeedstock (e.g., natural gas) in a cracking process (e.g., steamcracker) to yield a cracker effluent comprising a monomer (e.g.,ethylene); (b) flowing the monomer recovered from the cracker effluentto an oligomerization process; (c) contacting, in the oligomerizationprocess, the monomer and an oligomerization catalyst to yield anoligomerization reactor effluent comprising an oligomer (e.g.,1-hexene); (d) flowing the oligomer recovered from the oligomerizationreactor effluent to an aromatization process; and (e) contacting, in thearomatization process, the oligomer with an aromatization catalyst toyield an aromatization effluent comprising an arene (e.g., benzene). Inan aspect, the integrated converting systems of the present disclosureare continuous, serial-flow systems wherein the cracking process isconnected to the oligomerization process which is connected to thearomatization process wherein the cracker effluent, or a stream derivedtherefrom, flows into the oligomerization process and theoligomerization reactor effluent produced therein, or a stream derivedtherefrom, flows into the aromatization process. In some aspects asdescribed in more detail herein, an integrated converting system caninclude a hydrotreating process connected between the oligomerizationprocess and the aromatization process.

Throughout the systems, processes, and methods disclosed herein numerousstreams and products (e.g., ethylene, 1-hexene, benzene, ethylbenzene,styrene), are recovered from reactors and/or process streams. One havingordinary skill in the art will recognize that a stream or product may berecovered directly from a reactor or process in which it is formed;alternatively, the stream or product may be recovered (e.g., via aseparation process) from another process and/or stream locateddownstream of where it was formed.

II. Definitions

The following definitions are provided in order to aid those skilled inthe art in understanding the detailed description of the presentdisclosure. Unless otherwise defined herein, scientific and technicalterms used in connection with the present disclosure shall have themeanings that are commonly understood by those of ordinary skill in theart to which this disclosure belongs. Further, unless otherwise requiredby context, singular terms shall include pluralities and plural termsshall include the singular.

Further, certain features of the present disclosure which are, forclarity, described herein in the context of separate aspects, may alsobe provided in combination in a single aspect. Conversely, variousfeatures of the disclosure that are, for brevity, described in thecontext of a single aspect, may also be provided separately or in anysub-combination.

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997) can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Groups of elements of the periodic table are indicated using thenumbering scheme indicated in the version of the periodic table ofelements published in Chemical and Engineering News, 63(5), 27, 1985. Insome instances a group of elements may be indicated using a common nameassigned to the group; for example alkali earth metals (or alkalimetals) for Group 1 elements, alkaline earth metals (or alkaline metals)for Group 2 elements, transition metals for Group 3-12 elements, andhalogens for Group 17 elements.

General formulas C_(A+) and C_(A−) represent the number of carbon atomsin the molecular formula of an organic molecule (e.g., a hydrocarbon)where A is a whole number. For example, C₃₊ represents compounds withthree or more carbon atoms per molecule and C⁵⁻ represents compoundswith five or less carbon atoms per molecule

Unless explicitly stated otherwise in defined circumstances, allpercentages, parts, ratios, and like amounts used herein are defined byweight.

The term “olefin” whenever used in this specification and claims refersto compounds that have at least one carbon-carbon double bond that isnot part of an aromatic ring or ring system. The term “olefin” includesaliphatic and aromatic, cyclic and cyclic, and/or linear and branchedcompounds having at least one carbon-carbon double bond that is not partof an aromatic ring or ring system unless specifically stated otherwise.The term “olefin,” by itself, does not indicate the presence or absenceof heteroatoms and/or the presence or absence of other carbon-carbondouble bonds unless explicitly indicated. Olefins having only one, onlytwo, only three, etc. carbon-carbon double bonds can be identified byuse of the term “mono,” “di,” “tri,” etc. within the name of the olefin.The olefins can be further identified by the position of thecarbon-carbon double bond(s).

The term “reactor effluent,” and it derivatives (e.g. oligomerizationreactor effluent) generally refers to all the material which exits thereactor. The term “reactor effluent,” and its derivatives, can also beprefaced with other descriptors that limit the portion of the reactoreffluent being referenced. For example, while the term “reactoreffluent” would refer to all material exiting the reactor (e.g. productand solvent or diluent, among others), the term “olefin reactoreffluent” refers to the effluent of the reactor which contains an olefin(i.e. carbon-carbon) double bond.

The term “oligomerization,” and its derivatives, refers to processeswhich produce a mixture of products containing at least 70 weightpercent products containing from 2 to 30 monomer units. Similarly, an“oligomer” is a product that contains from 2 to 30 monomer units whilean “oligomerization product” includes all product made by the“oligomerization” process including the “oligomers” and products whichare not “oligomers” (e.g. product which contain more than 30 monomerunits). It should be noted that the monomer units in the “oligomer” or“oligomerization product” do not have to be the same. For example, an“oligomer” or “oligomerization product” of an “oligomerization” processusing ethylene and propylene as monomers can contain both ethyleneand/or propylene units.

The term “trimerization,” and it derivatives, refers to a process whichproduces a mixture of products containing at least 70 weight percentproducts containing three and only three monomer units. A “trimer” is aproduct which contains three and only three monomer units while a“trimerization product” includes all products made by the trimerizationprocess including trimer and product which are not trimer (e.g. dimersor tetramers). Generally, an olefin trimerization reduces number ofolefinic bonds, i.e., carbon-carbon double bonds, by two whenconsidering the number of olefin bonds in the monomer units and thenumber of olefin bonds in the trimer. It should be noted that themonomer units in the “trimer” or “trimerization product” do not have bethe same. For example, a “trimer” of a “trimerization” process usingethylene and butene as monomers can contain ethylene and/or butenemonomer units. That is to say the “trimer” will include C₆, C₈, C₁₀, andC₁₂ products. In another example, a “trimer” of a “trimerization”process using ethylene as the monomer can contain ethylene monomerunits. It should also be noted that a single molecule can contain twomonomer units. For example, dienes such as 1,3-butadiene and1,4-pentadiene have two monomer units within one molecule.

The term monomer refers to a C⁴⁻ hydrocarbon having a molecularstructure containing a single carbon-carbon double bond. For example,the monomer may be a C₂ monoolefin

The term oligomer refers to a C₆₊ hydrocarbon having a molecularstructure containing at least one carbon-carbon double bond. Forexample, the oligomer may be a C₆ monoolefin.

The term arene refers to monocyclic C₆ to C₁₄ aromatic compounds.

Cetane number is a measure of the ignition properties of diesel fuelrelative to cetane (C₁₆H₃₄), as a standard.

The smoke point of an oil or fat is the temperature at which, underspecific and defined conditions, it begins to produce a continuousbluish smoke that becomes clearly visible.

A further understanding of the aspects of the present disclosure can befound by referring to the attached schematic flow diagrams, incombination with the following descriptions. Various additional pumps,valves, heaters, coolers and other conventional equipment necessary forthe practice of the present disclosure herein will be familiar to oneskilled in the art. In some instances, said additional equipment mayhave been omitted from the drawings for the sake of clarity. Thedescriptions of the drawings provide one method for operating theprocess. However, it is understood that while these drawings are generalrepresentations of the process, minor changes can be made in adaptingthe drawings to the various conditions within the scope of thedisclosure. It is also understood that numerical references in thedrawings are consistent throughout the drawings. For example, an inletstream 10, comprising a hydrocarbon feedstock, is a hydrocarbonfeedstock inlet stream in all drawings. Unless otherwise explicitlydisclosed, the functions and components of a process (e.g., a processcomponent or unit) in one integrated converting system are substantiallythe same within another integrated converting system comprising thatprocess (e.g., the same process component or unit). In other words, thefunctions and components of cracking process 200 within integratedconverting system 1000 are substantially the same as the functions andcomponents of cracking process 200 within integrated converting system1100, or the functions and components of cracking process 200 withinintegrated converting system 1200, etc., unless otherwise explicitlydisclosed.

III. Integrated Converting System 1000

Referring to FIG. 1 , an integrated converting system 1000 is described.Integrated converting system 1000 generally comprises cracking process200, oligomerization process 300, aromatization process 400, andderivatization process 500.

In the integrated converting systems disclosed herein, various systemcomponents can be in fluid communication via one or more conduits (e.g.,pipes, tubing, flow lines, etc.) suitable for the conveyance of aparticular stream, for example as shown in detail by the numberedstreams in FIG. 1 .

A hydrocarbon feedstock 10 flows into cracking process 200 whereinhydrocarbons are converted (i.e., cracked), into monomers. In an aspect,the monomer comprises ethylene. Cracking process 200 may comprise anycracking process suitable for producing ethylene as disclosed herein.The cracking process 200 may be a steam cracker for converting one ormore hydrocarbons into ethylene. Methods of converting hydrocarbons intoethylene are disclosed in U.S. Pat. No. 6,790,342 which is incorporatedherein by reference in its entirety. Any method of producing ethylenedisclosed in U.S. Pat. No. 6,790,342 may be utilized herein. Thehydrocarbon feedstock 10 comprises any one or more hydrocarbons suitablefor use as disclosed herein. For example, the hydrocarbons may comprisenon-aromatic hydrocarbons, aromatic hydrocarbons, and a combinationthereof. The hydrocarbons may be derived from natural gas, gascondensates, gas oils, or combinations thereof. In an aspect, thehydrocarbons comprise ethane, propane, butanes, pentanes, naphthas, orcombinations thereof. In a further aspect, the hydrocarbon feedstock 10comprises ethane wherein the ethane may be derived from a source ofnatural gas.

In a particular aspect, an amount of ethane in the hydrocarbon feedstock10 is in a range of from about 10 wt. % to about 95 wt. %;alternatively, about 20 wt. % to about 80 wt. %, or alternatively, about40 wt. % to about 60 wt. %, based upon a total weight of the hydrocarbonfeedstock 10.

III.A. Cracking Process 200

Referring to FIG. 2 , an aspect of cracking process 200 is described.The hydrocarbon feedstock 10 is optionally combined with a hydrocarbonrecycle stream 201. The hydrocarbon recycle stream 201 may be comprisedof other streams of an integrated reforming system disclosed herein. Forexample, the hydrocarbon recycle stream 201 may be comprised of one ormore streams selected from the group consisting of a C₃₊ stream 262and/or an alternate C₃₊ stream 282 of cracking process 200; a heavieseffluent 336 and/or a by-product effluent 352 of FIG. 3 ; a C₂ effluent488 of FIG. 4 ; a polyalkylated stream 527 and/or an aromatics stream545 of FIG. 5 ; an ethane split stream 162 of FIG. 9 ; and combinationsthereof, all of which are further described herein. It is contemplatedthat some aspects of cracking process 200 may operate without thehydrocarbon recycle stream 201.

III.A.1. Flowscheme (1/2)

III.A.1.a. Cracking Zone & Effluent

Referring to FIG. 2 , the hydrocarbon feedstock 10 is diluted with steamand fed into cracking zone 205 comprising a steam cracker whereinheating to an elevated temperature in the absence of oxygen produces acracker effluent 210. Cracking zone 205 comprises one or more radiantfurnace reactors capable of producing the cracker effluent 210. Theproducts present in the cracker effluent 210 may vary depending upon thecomposition of the feed, the hydrocarbon-to-steam ratio, and on thecracking temperature and furnace residence time. In an aspect, crackingzone 205 may have a temperature in a range of from about 600° C. toabout 1500° C.; alternatively, about 750° C. to about 900° C. In afurther aspect, cracking zone 205 may have an inlet pressure in a rangeof from about 5 psig to about 400 psig (about 0.03 MPag to about 2.76MPag); or alternatively, about 29 psig to about 45 psig (about 0.19 MPagto about 0.31 MPag); and an outlet pressure in a range of from about 0.5psig to about 40 psig (about 0.0034 MPag to about 0.28 MPag); oralternatively, about 3.5 psig to about 11 psig (about 0.024 MPag toabout 0.076 MPag). Radiant furnace reactors are disclosed in U.S. Pat.Nos. 5,151,158; 4,780,196; 4,499,055; 3,274,978; 3,407,789; and3,820,955, each of which is incorporated herein by reference in itsentirety. In an aspect, the cracker effluent 210 comprises one or moremonomers, hydrogen, methane, acetylene, ethane, C₃₊ saturatedhydrocarbons, steam, and combinations thereof. In a further aspect, themonomer(s) comprises ethylene, propylene, butene, or combinationsthereof; or alternatively, ethylene.

An amount of ethylene in the cracker effluent 210 may be in a range offrom about 10 wt. % to about 95 wt. %; alternatively, about 20 wt. % toabout 80 wt. %; or alternatively, about 40 wt. % to about 70 wt. %,based upon a total weight of the cracker effluent 210. In a furtheraspect, the cracker effluent 210 may comprise from about 1 wt. % toabout 20 wt. % hydrogen, from about 1 wt. % to about 30 wt. % methane,from about 1 wt. % to about 30 wt. % acetylene, from about 3 wt. % toabout 45 wt. % ethane, from about 0 wt. % to about 25 wt. % C₃hydrocarbons, and from about______wt. % to about______wt. % steam.

III.A.2. Flowscheme (2/2)

The cracker effluent 210 flows into quenching zone 215 to produce aquenched gas stream 220. In an aspect, an operating temperature ofquenching zone 215 may be less than necessary to sustain a crackingreaction occurring within the cracker effluent 210. In an aspect, thecracker effluent 210 is cooled to a temperature below about 595° C.;alternatively, to a temperature in a range of about 30° C. to about 110°C. to form the quenched gas stream 220. Quenching can be effected by anymeans suitable to one having ordinary skill in the art. For example, thecracker effluent 210 may be passed to a quench boiler and quench towerwhere dilution steam can be removed and recycled back to the crackingfurnaces. Methods for cooling the cracker effluent 210 are disclosed inU.S. Pat. Nos. 3,407,798; 5,427,655; 3,392,211; 4,351,275; and3,403,722, each of which is incorporated herein by reference in itsentirety. The quenched gas stream 220 flows into first compression zone225 to produce a pressurized gas stream 230. In an aspect, thepressurized gas stream 230 may comprise a pressure in a range of fromabout 150 psig to about 650 psig (about 1.034 MPag to about 4.48 MPag).First compression zone 225 comprises one or more gas compressors whereinthe gas compressors may be any gas compressor suitable for use asdisclosed herein.

The pressurized gas stream 230 flows into de-acidifying zone 235 whereinhydrogen sulfide (H₂S) and carbon dioxide (CO₂) are removed to produce awet gas stream 240. In an aspect, de-acidifying zone 235 removes aportion of the H₂S and CO₂ within the pressurized gas stream 230. In afurther aspect the wet gas stream 240 may have a H₂S concentration ofless than about 0.1 ppm by weight; alternatively, in a range of about 25ppb to about 100 ppb by weight. In yet a further aspect, the wet gasstream 240 may have a CO₂ concentration of less than about 5 ppm byweight. Removal of H₂S and CO₂ may be effected by any suitable means asdetermined by one having ordinary skill in the art and with the aid ofthis disclosure. In yet a further aspect, diethanolamine or causticcontactors may be used to remove at least a portion of the H₂S and CO₂comprising the pressurized gas stream 230. The wet gas stream 240 flowsinto drying zone 245 to produce a cracked gas stream 250. In an aspect,the water content of the cracked gas stream 250 is less than an amountneeded to effect downstream operational problems. In a further aspect,the water content of the cracked gas stream 250 is less than about 10ppm by weight. Drying in drying zone 245 may be effected by any suitablemeans as determined by one having ordinary skill in the art and with theaid of this disclosure. In an aspect, molecular sieve beds can beutilized to remove water from the wet gas stream 240.

The cracked gas stream 250 flows into deethanizer zone 255 to produce aC²⁻ stream 260 and a C₃₊ stream 262. Deethanizer zone 255 comprises afractionator capable of producing the C²⁻ stream 260 and the C₃₊ stream262. The C²⁻ stream 260 may comprise hydrogen, methane, ethane,acetylene, ethylene or combinations thereof. The C₃₊ stream 262comprises C₃ hydrocarbons and heavier constituents and, in an aspect,may be combined with the hydrocarbon recycle stream 201. The C²⁻ stream260 flows into hydrogenation zone 265 wherein a portion of the acetylenewithin the C²⁻ stream 260 may be removed. An ethylene stream 270 isrecovered from hydrogenation zone 265. Hydrogenation of the C²⁻ stream260 may be performed by any means suitable as determined by one havingordinary skill in the art and with the aid of this disclosure. Forexample, an acetylene reactor containing a selective hydrogenationcatalyst can be utilized to hydrogenate a portion of the acetylenewithin the C²⁻ stream 260 selectively to ethylene (in preference tohydrogenation to acetylene to ethane). Typically, Group VIII metalhydrogenation catalysts are utilized. Selective hydrogenation catalystsare disclosed in U.S. Pat. Nos. 3,679,762; 4,571,442; 4,347,392;4,128,595; 5,059,732; 5,488,024; 5,489,565; 5,520,550; 5,583,274;5,698,752; 5,585,318; 5,587,348; 6,127,310 and 4,762,956, each of whichis incorporated herein by reference in its entirety. Operatingconditions in hydrogenation zone 265 may be any combination ofconditions suitable as determined by one having ordinary skill in theart and with the aid of this disclosure. In an aspect, the temperatureand pressure in hydrogenation zone 265 may be at levels capable tohydrogenate a portion of the acetylene in the C²⁻ stream 260 toethylene. In a further aspect, hydrogenation zone 265 may have atemperature in a range of from about 10° C. to about 205° C. In yet afurther aspect, hydrogenation zone 265 may have a pressure in a range ofabout from 360 psig to about 615 psig (about 2.48 MPag to about 4.24MPag). In some aspects, an amount of acetylene remaining in the ethylenestream 270 may be less than about 5 ppm by weight; alternatively, in arange of from about 0.5 ppm to about 3 ppm by weight.

Alternatively, all or a portion of the C²⁻ stream 260 is routed throughline 266 with valves in streams 260 and 268 and flows into secondcompression zone 267 to produce a pressurized C²⁻ stream 268. Thepressurized C²⁻ stream 268 may have a pressure in a range of from about100 psig to about 750 psig (about 0.68 MPag to about 5.17 MPag);alternatively, from about 200 psig to about 650 psig (about 1.37 MPag toabout 4.48 MPag). Second compression zone 267 comprises one or more gascompressors, wherein the gas compressors may be any gas compressorsuitable for use as disclosed herein. The pressurized C²⁻ stream 268flows into hydrogenation zone 265 wherein a portion of the acetylenecomprising the pressurized C²⁻ stream 268 is removed (e.g., viaselective hydrogenation to ethylene). The ethylene stream 270 isrecovered from hydrogenation zone 265 as disclosed herein.

In another alternative, all or a portion of the effluent of drying zone245 is an alternate gas stream 272. The alternate gas stream 272 flowsinto alternate hydrogenation zone 275 wherein a portion of the acetylenecomprising the alternate gas stream 272 is removed to produce a reducedgas stream 276. In an aspect, alternate hydrogenation zone 275 operatescomparably to hydrogenation zone 265. The reduced gas stream 276 flowsinto alternate deethanizer zone 277 wherein an alternate ethylene stream280 is recovered and an alternate C₃₊ stream 282 is produced. In anaspect, alternate deethanizer zone 277 operates comparably todeethanizer zone 255. In a further aspect, the compositions of thealternate ethylene stream 280 and the alternate C₃₊ stream 282 arecomparable to the compositions of the ethylene stream 270 and the C₃₊stream 262, respectively. In an aspect, the alternate C₃₊ stream 282 maybe combined with hydrocarbon recycle stream 201. The ethylene stream 270and/or the alternate ethylene stream 280 flows into a cracking processeffluent 25.

III.A.3. Effluent Composition

In an aspect, the cracking process effluent 25 comprises ethylene. Anamount of ethylene in the cracking process effluent 25 may be in a rangeof from about 30 wt. % to about 95 wt. %; alternatively, about 30 wt. %to about 70 wt. %; or alternatively, about 40 wt. % to about 60 wt. %,based upon a total weight of the cracking process effluent 25.

III.B. Oligomerization Process 300

Returning to FIG. 1 , the cracking process effluent 25 flows intooligomerization process 300 wherein monomers (e.g., ethylene) areconverted into oligomers (e.g., 1-hexene). In an aspect, the crackingprocess effluent 25 flows continuously out of cracking process 200 andinto oligomerization process 300. One having ordinary skill in the artwill appreciate that, as presently described for the cracking processeffluent 25, each stream described throughout the present disclosureflows continuously from one process to the next. The continuous flow ofeach stream is not explicitly stated for the sake of simplicity, but isa feature of each stream. Oligomerization process 300 may comprise atrimerization process whereby an ethylene monomer is contacted with anoligomerization catalyst in an oligomerization reactor to produce a1-hexene oligomer. In an aspect, the trimerization process comprises atrimerization reaction. For the purposes of the present disclosure theterms oligomerization and trimerization are used interchangeably.Oligomerization process 300 may comprise any trimerization processand/or trimerization reaction suitable for producing 1-hexene asdisclosed herein. Methods of converting ethylene into 1-hexene utilizingan oligomerization catalyst system are disclosed in U.S. Pat. No.7,157,612 which is incorporated herein by reference in its entirety.

Optionally, the cracking process effluent 25 may be further divided intoan ethylene feed 27 and/or a utility ethylene stream 29. The ethylenefeed 27 comprising ethylene flows into derivatization process 500. Theutility ethylene stream 29 comprising ethylene may be routed to storageor for sale.

III.B.1 Flowscheme (1/2)

Referring to FIG. 3 , an aspect of oligomerization process 300 isdescribed. The cracking process effluent 25 optionally may be combinedwith an ethylene recycle stream 306 to form an oligomerization feedstream 301. In an aspect, the ethylene recycle stream 306 may becombined with one or more streams selection from the group consisting ofan ethylene effluent 340; a C₂ effluent 488 of FIG. 4 ; an ethylenesplit stream 165 of FIG. 9 ; and combinations thereof, as furtherdescribed herein. In a further aspect, the ethylene recycle stream 306comprises a light effluent of a polyethylene polymerization process. Itis contemplated that some aspects of oligomerization process 300 mayoperate without the ethylene recycle stream 306. The oligomerizationfeed stream 301 flows into oligomerization reactor 305. In an aspect,the oligomerization feed stream 301 comprises ethane, ethylene or acombination thereof. A first hydrogen feed stream 302 flows intooligomerization reactor 305. The hydrogen feed stream 302 may be fed tothe oligomerization reactor 305 as a separate feed stream, or may becombined with oligomerization feed stream 301 and fed to theoligomerization reactor as a combined feed stream. In an aspect, thefirst hydrogen feed stream 302 may be combined with a stream fromanother section of an integrated reforming system of the presentdisclosure. For example, the first hydrogen feed stream 302 may becombined with one or more streams selected from the group consisting ofa hydrogen effluent 41 of FIG. 4 ; an efflux hydrogen stream 537 of FIG.5 ; and combinations thereof, as further described herein. Withoutwishing to be limited by theory, performing an oligomerization reactionin the presence of hydrogen may enhance product selectivity, reduceformation of polymeric products, or both. It is contemplated that someaspects of oligomerization process 300 may operate without the firsthydrogen feed stream 302.

In an aspect of oligomerization process 300 ethylene is contacted withan oligomerization catalyst in oligomerization reactor 305 in thepresence of a solvent. In such aspect, a solvent feed 308 is combinedwith an oligomerization catalyst stream 304. For the purposes of thepresent disclosure, “solvent” refers to a diluent or a medium in whichthe oligomerization reaction occurs. The solvent may be any inertsolvent suitable for use in an oligomerization reaction as disclosedherein. In an aspect, the solvent is not necessarily an inert material,and the solvent may participate in the oligomerization. In a furtheraspect, the solvent may be n-alkanes, branched alkanes, an iso-paraffin,a paraffin, a cycloparaffin, an aromatic hydrocarbon, or combinationsthereof. In a further aspect, the solvent may be isobutane, cyclohexane,methylcyclohexane, 2,2,4-trimethylpentane, or combinations thereof. Inan aspect where 1-hexene is the product of the oligomerization reaction,the 1-hexene formed therein (i.e., the reaction product) may also serveas the solvent and in such aspect, the oligomerization reaction may betermed a “solventless” oligomerization reaction. Alternatively, in anaspect where 1-hexene is the product of the oligomerization reaction,the solvent is cyclohexane. In an aspect, the solvent feed 308 may becombined with one or more streams selected from the group consisting ofa solvent effluent 354; a cyclohexane recycle stream 123 of FIG. 7 ;with a raffinate stream 419 of FIG. 10 ; and combinations thereof, asfurther disclosed herein. It is contemplated that some aspects ofoligomerization process 300 may operate without the solvent feed 308.

III.B.2. Catalyst System

The oligomerization catalyst stream 304 flows into oligomerizationreactor 305. Oligomerization catalyst systems suitable for thetrimerization of ethylene to 1-hexene are described in U.S. Pat. No.7,157,612 as disclosed herein. In an aspect, an oligomerization catalystsystem of the present disclosure comprises a chromium source, apyrrole-containing compound and a metal alkyl, all of which have beencontacted and/or reacted in the presence of an unsaturated hydrocarbon.Optionally, the oligomerization catalyst system may be supported on aninorganic oxide support.

The chromium source can be one or more organic or inorganic compounds,wherein the chromium oxidation state is from 0 to 6. Generally, thechromium source will have a formula of CrX_(n), wherein X can be thesame or different and can be any organic or inorganic radical, and n isan integer from 1 to 6. In an aspect, the organic radicals may have fromabout 1 to about 20 carbon atoms per radical, and are selected from thegroup consisting of alkyl, alkoxy, ester, ketone, and/or amido radicals.The organic radicals may be straight-chained or branched, cyclic oracyclic, aromatic or aliphatic, may be made of mixed aliphatic,aromatic, and/or cycloaliphatic groups. In a further aspect, theinorganic radicals include, but are not limited to halides, sulfates,and/or oxides.

In an aspect, the chromium source is a chromium (II)- and/or chromium(III)-containing compound which can yield a catalyst system withtrimerization activity suitable for use herein. In a further aspect, thechromium source is a chromium (III) compound because of ease of use,availability, and enhanced catalyst system activity. Non-limitingexamples of chromium (III) compounds suitable for use in the presentdisclosure include chromium carboxylates, chromium naphthenates,chromium halides, chromium pyrrolides, and/or chromium dionates. In anaspect, the chromium (III) compound may be chromium (III)2,2,6,6,-tetramethylheptanedionate [Cr(TMHD)₃], chromium (III)2-ethylhexanoate [Cr(EH)₃, also referred to as chromium (III)tris(2-ethylhexanoate),] chromium (III) naphthenate [Cr(NP)₃], chromium(III) chloride, chromic bromide, chromic fluoride, chromium (III)acetylacetonate, chromium (III) acetate, chromium (III) butyrate,chromium (III) neopentanoate, chromium (III) laurate, chromium (III)stearate, chromium (III) oxalate, or combinations thereof. In a furtheraspect, the chromium (III) compound may be a chromium (III) pyrrolide.

Non-limiting examples of chromium (II) compounds suitable for use in thepresent disclosure include chromous bromide, chromous fluoride, chromouschloride, chromium (II) bis(2-ethylhexanoate), chromium (II) acetate,chromium (II) butyrate, chromium (II) neopentanoate, chromium (II)laurate, chromium (II) stearate, chromium (II) oxalate, or combinationsthereof. In a further aspect, the chromium (II) compound may be achromium (II) pyrrolide.

The pyrrole-containing compound may be any pyrrole-containing compound,or pyrrolide, that will react with a chromium source to form a chromiumpyrrolide complex. As used in this disclosure, the term“pyrrole-containing compound” may refer to hydrogen pyrrolide, (i.e.,pyrrole (C₄H₅N)), derivatives of hydrogen pyrrolide, substitutedpyrrolides, or metal pyrrolide complexes. As used in this disclosure,the term “pyrrolide” refers to a 5-membered, nitrogen-containingheterocycle, such as for example, pyrrole, derivatives of pyrrole, andmixtures thereof. Broadly, the pyrrole-containing compound may bepyrrole and/or any heteroleptic or homoleptic metal complex or salt,containing a pyrrolide radical, or ligand. The pyrrole-containingcompound may be either affirmatively added to the reactor, or generatedin-situ.

Generally, the pyrrole-containing compound will have from about 4 toabout 20 carbon atoms per molecule. In an aspect, a pyrrolide suitablefor use in the present disclosure may be selected from the groupconsisting of hydrogen pyrrolide (pyrrole), lithium pyrrolide, sodiumpyrrolide, potassium pyrrolide, cesium pyrrolide, and/or the salts ofsubstituted pyrrolides, because of high reactivity and activity with theother reactants. Examples of substituted pyrrolides suitable for useinclude, but are not limited to, pyrrole-2-carboxylic acid,2-acetylpyrrole, pyrrole-2-carboxyaldehyde, tetrahydroindole,2,5-dimethylpyrrole, 2,4-dimethyl-3-ethylpyrrole,3-acetyl-2,4-dimethylpyrrole,ethyl-2,4-dimethyl-5-(ethoxycarbonyl)-3-pyrrole-proprionate,ethyl-3,5-dimethyl-2-pyrrolecarboxylate, or combinations thereof. Whenthe pyrrole-containing compound contains chromium, the resultantchromium compound can be called a chromium pyrrolide.

In an aspect, the pyrrole-containing compounds used in the catalystsystem are selected from the group consisting of hydrogen pyrrolide,i.e., pyrrole (C₄H₅N), 2,5-dimethylpyrrole and/or chromium pyrrolides,all of which may provide enhanced trimerization activity. Optionally,for ease of use, a chromium pyrrolide can provide both the chromiumsource and the pyrrole-containing compound. As used in this disclosure,when a chromium pyrrolide is used to form the catalyst system, achromium pyrrolide is considered to provide both the chromium source andthe pyrrole-containing compound. While all pyrrole-containing compoundsmay produce catalyst systems with high activity and productivity, use ofpyrrole and/or 2,5-dimethylpyrrole may produce a catalyst systemdesirable levels of activity and selectivity to one or more desiredproducts.

In an aspect, the metal alkyl comprises a heteroleptic or homolepticmetal alkyl compound. In a further aspect, any heteroleptic orhomoleptic metal alkyl suitable for use as described herein may beutilized. In a further aspect, one or more metal alkyls may be used. Thealkyl ligand(s) on the metal may be aliphatic and/or aromatic. In afurther aspect, the alkyl ligand(s) may be any saturated or unsaturatedaliphatic radical. The metal alkyl may have any number of carbon atoms.However, due to commercial availability and ease of use, the metal alkylwill usually comprise less than about 70 carbon atoms; alternatively,less than 20 carbon atoms per metal alkyl molecule. Non-limitingexamples of metal alkyls suitable for use herein include, alkylaluminumcompounds, alkylboron compounds, alkyl magnesium compounds, alkyl zinccompounds and/or alkyl lithium compounds. In a further aspect, the metalalkyl comprises n-butyl lithium, s-butyllithium, t-butyllithium,diethylmagnesium, diethylzinc, triethylaluminum, trimethylaluminum,triisobutylalumium, or combinations thereof.

In a further aspect, the metal alkyl may be a non-hydrolyzed metalalkyl, i.e., not pre-contacted with water. In some aspects, the metalalkyl may be selected from the group consisting of non-hydrolyzedalkylaluminum compounds, non-hydrolyzed derivatives of alkylaluminumcompounds, non-hydrolyzed halogenated alkylaluminum compounds, orcombinations mixtures thereof. In a further aspect, use of thenon-hydrolyzed metal alkyl may improve product selectivity and/or,catalyst system reactivity, activity, and/or productivity. Withoutwishing to be limited by theory, the use of hydrolyzed metal alkyls canresult in decreased olefin, (i.e., liquids), production and increasedpolymer, (i.e., solids), production.

In an aspect, the metal alkyl comprises a non-hydrolyzed alkylaluminumcompound, expressed by the general formulae AlR₃, AlR₂X, AlRX₂, AlR₂OR,AlRXOR, and/or Al₂R₃X₃, wherein R is an alkyl group and X is a halogenatom. Non-limiting examples of metal alkyls suitable for use hereininclude triethylaluminum, tripropylaluminum, tributylaluminum,diethylaluminum chloride, diethylaluminum bromide, diethylaluminumethoxide, diethylaluminum phenoxide, ethylaluminum dichloride,ethylaluminum sesquichloride, or combinations thereof. In a particularaspect, the alkylaluminum compound may be triethylaluminum.

In a further aspect, an unsaturated hydrocarbon is present duringcontacting and/or reacting of the chromium source, thepyrrole-containing compound and the metal alkyl, wherein contactingand/or reacting may be performed in any manner suitable for the purposesof the present disclosure. For example, the pyrrole-containing compoundcan be contacted with the chromium source and then with the metal alkyl.Optionally, the pyrrole-containing compound can be contacted with themetal alkyl and then with the chromium source. Numerous other contactingprocedures can be used, such as for example, contacting alloligomerization catalyst system components in oligomerization reactor305.

The unsaturated hydrocarbon may be any aromatic or aliphatichydrocarbon, in a gas, liquid or solid state. In an aspect, theunsaturated hydrocarbon in a liquid state effects thorough contacting ofthe chromium source, the pyrrole-containing compound, and the metalalkyl. The unsaturated hydrocarbon can have any number of carbon atomsper molecule. The unsaturated hydrocarbon may comprise less than about70 carbon atoms; alternatively, less than 20 carbon atoms per metalalkyl molecule, due to commercial availability and ease of use.Non-limiting examples of unsaturated, aliphatic hydrocarbons suitablefor use herein include ethylene, 1-hexene, 1,3-butadiene, orcombinations thereof. In an aspect, the unsaturated aliphatichydrocarbon may be 1-hexene which may be produced within theoligomerization reactor. Without wishing to be limited by theory,aromatic hydrocarbons may improve the stability, the activity, and/orthe selectivity of the catalyst system. Non-limiting examples ofaromatic hydrocarbons suitable for use herein include toluene, benzene,xylene, ethylbenzene, mesitylene, hexamethylbenzene, or combinationsthereof. In an aspect, the aromatic hydrocarbon may be toluene orethylbenzene; alternatively, toluene; or alternatively, ethylbenzene.

In a particular aspect, the oligomerization catalyst system mayoptionally comprise a halide source. Without wishing to be limited bytheory, the presence of a halide source may improve the stability, theactivity, and/or the selectivity of the oligomerization catalyst system.The halide source can be any compound containing a halogen. For example,the halide source may comprise fluoride, chloride, bromide, iodide, orcombinations thereof. In a further aspect, the halide source may bechloride or bromide; alternatively, chloride; or alternatively, bromide.

Non-limiting examples of a halide source suitable for use herein includecompounds with a general formula of R_(m)X_(n), wherein R can be anyorganic and/or inorganic radical, X can be a halide, selected from thegroup consisting of fluoride, chloride, bromide, and/or iodide, and m+ncan be any number greater than 0. When R is an organic radical, R hasfrom about 1 to about 70 carbon atoms per radical; alternatively, from 1to 20 carbon atoms per radical. When R is an inorganic radical, R may beselected from the group consisting of aluminum, silicon, germanium,hydrogen, boron, lithium, tin, gallium, indium, lead, or combinationsthereof. In an aspect, the halide source may be methylene chloride,chloroform, benzylchloride, silicon tetrachloride, tin(II) chloride,tin(IV) chloride, germanium tetrachloride, boron trichloride, aluminumtribromide, aluminum trichloride, 1,4-di-bromobutane, 1-bromobutane orcombinations thereof. In a further aspect, the halide source may be atin (IV) halide, a germanium halide, or a combination thereof.

In a still further aspect, the halide source may be provided by thechromium source, the metal alkyl, the unsaturated hydrocarbon, orcombinations thereof. In an aspect, the halide source may be analkylaluminum halide used in conjunction with an alkylaluminum compound.Non-limiting examples of alkylaluminum halides suitable for use as thehalide source include but are not limited to diisobutylaluminumchloride, diethylaluminum chloride, ethylaluminum sesquichloride,ethylaluminum dichloride, diethylaluminum bromide, diethylaluminumiodide, or combinations thereof.

One having ordinary skill in the art will appreciate that a reactionmixture comprising the chromium source, the pyrrole-containing compound,the metal alkyl, the unsaturated hydrocarbon and the optional halidesource may further comprise additional components which do not adverselyaffect, and may enhance, the oligomerization catalyst system asdisclosed herein.

III.B.2.a. Catalyst Component Ratios

In an aspect, the oligomerization catalyst system comprises a molarratio of pyrrole-containing compound to chromium in the chromium sourcein a range of from about 1:1 to about 80:1; alternatively, about 3:1 toabout 50:1; or alternatively, about 10:1 to about 20:1. In a furtheraspect, the molar ratio of pyrrole-containing compound to chromium inthe chromium source may be about 16:1; or alternatively, about 3:1. Inyet a further aspect, the oligomerization catalyst system comprises amolar ratio of metal alkyl to chromium in the chromium source in a rangeof from about 5:1 to about 200:1; alternatively, about 10:1 to about100:1; or alternatively, about 40:1 to about 60:1. In an aspect, themolar ratio of metal alkyl to chromium in the chromium source may beabout 50:1; or alternatively, about 11:1. In a still further aspect, theoligomerization catalyst system comprises a molar ratio of halide sourceto chromium in the chromium source in a range of from about 2:1 to about300:1; alternatively, about 5:1 to about 200:1; or alternatively, about50:1 to about 80:1. In an aspect, the molar ratio of halide source tochromium in the chromium source may be about 63:1; or alternatively,about 8:1.

III.B.3. Oligomerization Reactor Conditions

Within oligomerization reactor 305 contacting of ethylene and anoligomerization catalyst system may occur in any manner suitable andwith the aid of the present disclosure. In an aspect, contacting ofethylene and the oligomerization catalyst system may occur by solutionreaction, slurry reaction, gas phase reaction, or combinations thereof.In a particular aspect, a suspension formed between the oligomerizationcatalyst system and a solvent may be agitated to maintain a uniformoligomerization catalyst system concentration throughout the suspension;or alternatively, a solution formed between the oligomerization catalystsystem and a solvent may be agitated to maintain the oligomerizationcatalyst system in solution throughout the oligomerization process. Thetemperature within oligomerization reactor 305 may be any temperaturesuitable for a trimerization reaction of ethylene. In an aspect, thetemperature is in range that is low enough to avoid decreases in theactivity of the oligomerization catalyst system and high enough to avoidformation and/or precipitation of polymeric products. In a furtheraspect, the temperature within oligomerization reactor 305 may be in arange of from about 0° C. to about 300° C.; alternatively, from about60° C. to about 275° C.; or alternatively, from about 110° C. to about125° C. The pressure within oligomerization reactor 305 may be anypressure suitable for a trimerization reaction of ethylene. In anaspect, the pressure is in range that is high enough to avoid decreasesin activity of the oligomerization catalyst system. In a further aspect,the pressure within oligomerization reactor 305 may be in a range offrom about atmospheric to about 2500 psig (about 0.101 MPag to about17.24 MPag). When using 1-hexene as the diluent, the pressure may be ina range of from about atmospheric to about 2000 psig (about 0.101 MPagto about 13.79 MPag); alternatively, from about 1100 psig to about 1600psig (about 7.58 MPag to about 11.03 MPag). When using a diluent otherthan 1-hexene, the pressure may be in a range of from about atmosphericto about 1500 psig (about 0.101 MPag to about 10.34 MPag);alternatively, from about 600 psig to about 1000 psig (about 4.13 MPagto about 6.9 MPag).

III.B.4. Flowscheme (2/2)

Returning to FIG. 3 , an oligomerization reactor effluent stream 310flowing from oligomerization reactor 305 comprises all components thatcan be present in and can be removed from an oligomerization reactor.The oligomerization reactor effluent stream 310 may compriseoligomerization product(s), by-product(s), co-product(s),side-product(s), light hydrocarbons, heavy hydrocarbons, unreactedmonomer(s), catalyst system, solvent and other reactor components. In anaspect, the oligomerization reactor effluent stream 310 comprises1-hexene, cyclohexane and unreacted ethylene; or alternatively, 1-hexeneand unreacted ethylene. It will be appreciated by one having skill inthe art that streams 301, 302, 304, and 310 may be located anywhere onoligomerization reactor 305 suitable to allow the ethylene to thoroughlycontact the oligomerization catalyst system within oligomerizationreactor 305. A catalyst kill stream 312 is combined the oligomerizationreactor effluent stream 310. The catalyst kill stream 312 comprises acatalyst deactivation composition that may deactivate, either partiallyor completely, the oligomerization catalyst system as disclosed herein.It is contemplated that some aspects of oligomerization process 300 maynot utilize the catalyst kill stream 312. Filter 315 can removeparticulates (e.g., catalyst fines and undesirable polymeric products)from the oligomerization reactor effluent stream 310. While not wishingto be bound by theory, it is believed that higher reactor and streamtemperatures can inhibit solidification of undesirable polymerparticles. When the oligomerization reactor effluent stream 310 ismaintained at high temperature, fewer particulates can form and filter315 may be unnecessary. In aspects where process conditions favorparticulate formation (e.g., cooling of the oligomerization reactoreffluent stream 310), filter 315 can be used. It is contemplated thatsome aspects of oligomerization process 300 may not utilize filter 315.The process stream 320 comprises the effluent of filter 315 or acontinuation of the oligomerization reactor effluent stream 310 whereinthe process stream 320 comprises little or no particulates.

The process stream 320 flows into a first separator 325 to produce alight effluent 330 and a heavies effluent 336. The heavies effluent 336comprises heavy hydrocarbons and the oligomerization catalyst system.The light effluent 330 may comprise 1-hexene, unreacted ethylene,undesired oligomerization products, solvent, and combinations thereof.In an aspect, the light effluent 330 comprises methane, ethane,ethylene, propane, propylene, butane, or combinations thereof. In afurther aspect, the first separator 325 comprises a washing process thatfacilitates removal of the oligomerization catalyst system from thelight effluent 330 (e.g., 1-hexene). For the purposes of the presentdisclosure heavies present in heavies effluent 336 may comprise C₈₊hydrocarbons, C₈₊ oligomers formed by the oligomerization, polymericproducts or combinations thereof. In an aspect, the C₈₊ oligomers formedby the oligomerization reaction include octenes, decenes, dodecenes andtetradecenes. The terms heavies and heavy hydrocarbons are usedinterchangeably throughout the present disclosure. In an aspect, theheavies effluent 336 may be combined with hydrocarbon recycle stream 201of FIG. 2 as disclosed herein. In an aspect, a heavies feed 322 is anoptional inlet into the first separator 325. The heavies feed 322 maycomprise the desired 1-hexene product and/or a heavies component asdescribed herein. In an aspect, the heavies feed 322 may be an effluentof a polyethylene production plant.

The light effluent 330 flows into a second separator 335 to produce anethylene effluent 340 and a hexene effluent 342. The ethylene effluent340 may be combined with the ethylene recycle stream 306. In a furtheraspect, the ethylene effluent 340 may be routed to storage or for sale,for example alone or in combination with utility ethylene stream 29 ofFIG. 2 . The hexene effluent 342 flows into a third separator 345wherein a 1-hexene effluent 35 is recovered. The third separator 345produces a by-product effluent 352 comprising undesired products of theoligomerization reaction. In an aspect, the by-product effluent 352 maybe combined with the hydrocarbon recycle stream 201 of FIG. 2 , asdisclosed herein. In an aspect, a solvent effluent 354 is recovered fromthe third separator 345 wherein the solvent may comprise cyclohexane. Inan aspect, the third separator 345 facilitates removal of the solventfrom the 1-hexene effluent 35. The solvent effluent 354 may be combinedwith the solvent feed 308 as disclosed herein. The first separator 325,second separator 335, and third separator 345 may operate in any mannersuitable for producing the effluents thereof. In a further aspect, eachof the first separator 325, second separator 335, and third separator345 comprise at least one fractionator or distillation column.

Alternatively, some aspects of oligomerization process 300 operate inthe absence of one or more of the filter 315, the first separator 325,the second separator 335, and the third separator 345 wherein the1-hexene effluent 35 may be recovered directly from the oligomerizationreactor effluent stream 310. In such aspects, the 1-hexene effluent 35further comprises any components that may be within the oligomerizationreactor effluent stream 310 as disclosed herein.

It is contemplated that oligomerization process 300 may be utilized: 1)with monomers other than ethylene; 2) to produce oligomers other than1-hexene; and/or 3) to perform oligomerization reactions other thantrimerization reactions.

III.B.5. Effluent Composition

In an aspect, the 1-hexene effluent 35 may comprise C₆ olefins whereinan amount of C₆ olefins may be at least 60 wt. %; alternatively, atleast 70 wt. %; alternatively, at least 75 wt. %; alternatively, atleast 80 wt. %; alternatively, at least 85 wt. %; or alternatively, atleast 90 wt. %, based upon a total weight of the 1-hexene effluent 35.In a further aspect, an amount of C₆ olefins in the 1-hexene effluent 35may be in range of from about 60 wt. % to about 99.9 wt. %;alternatively, from about 70 wt. % to about 99.8 wt. %; alternatively,from about 75 wt. % to about 99.7 wt. %; or alternatively, from about 80wt. % to about 99.6 wt. %; or alternatively, from about 85 wt. % toabout 99.6 wt. %. In a further aspect, the 1-hexene effluent 35 maycomprise 1-hexene wherein an amount of 1-hexene may be at least 85 wt.%; alternatively, at least 87.5 wt. % alternatively, at least 90 wt. %;alternatively, at least 92.5 wt. %; alternatively, at least 95 wt. %;alternatively, at least 97 wt. %; or alternatively, at least 98 wt. %.In an aspect, the amount of 1-hexene in the 1-hexene effluent 35 may bein a range of from about 85 wt. % to about 99.9 wt. %; alternatively,about 87.5 wt. % to about 99.9 wt. %; alternatively, about 90 wt. % toabout 99.9 wt. %; alternatively, about 92.5 wt. % to about 99.9 wt. %;alternatively, about 95 wt. % to about 99.9 wt. %; alternatively, about97 wt. % to about 99.9 wt. %; or alternatively, about 98 wt. % to about99.9 wt. %.

III.C. Aromatization Process 400

Returning to FIG. 1 , the 1-hexene effluent 35 flows into aromatizationprocess 400. In an aspect, aromatization process 400 comprises anaromatization reactor system wherein acyclic oligomers are contactedwith an aromatization catalyst and undergo thereby an aromatizationreaction that produces arenes. In a further aspect, the aromatizationreaction converts 1-hexene into benzene. Methods for converting 1-hexeneinto benzene are disclosed in U.S. Pat. No. 7,932,425 which isincorporated herein by reference in its entirety. Any suitable method ofproducing benzene disclosed in U.S. Pat. No. 7,932,425 may be utilizedherein. It is contemplated that aromatization process 400 may beutilized with acyclic hydrocarbons other than 1-hexene to produce arenesother than benzene.

In an aspect, an auxiliary aromatization feed 37 flows intoaromatization process 400. The auxiliary aromatization feed 37 maycomprise non-aromatic hydrocarbons containing at least six carbon atoms.In a further aspect, the auxiliary aromatization feed 37 may comprise amixture of hydrocarbons comprising C₆ to C₈ hydrocarbons comprising upto about 15 wt. % of C⁵⁻ hydrocarbons and up to about 10 wt. % of C₉₊hydrocarbons wherein weight percentage is based upon a total weight ofthe auxiliary aromatization feed 37. In a particular aspect, theauxiliary aromatization feed 37 may comprise a naphtha feed. In anaspect, the naphtha feed may be a light naphtha with a boiling range ofabout 70° F. to about 450° F. (about 21.1° C. to about 232.2° C.),wherein the naphtha feed may contain aliphatic, naphthenic, orparaffinic hydrocarbons. It is contemplated that some aspects ofaromatization process 400 may operate without the auxiliaryaromatization feed 37.

III.C.1 Flowscheme

III.C.1.a. Reactor System

Referring to FIG. 4 , an aspect of aromatization process 400 isdescribed. In the aspect shown, the aromatization reactor systemcomprises a catalytic reactor system wherein four aromatization reactorsare serially connected; reactors 410, 420, 430, and 440. However, thecatalytic reactor system may comprise any suitable number andconfiguration of aromatization reactors, for example one, two, three,five, six, or more reactors in series or in parallel. As aromatizationreactions are highly endothermic, large temperature drops occur acrossthe reactors 410, 420, 430, and 440. Therefore, each reactor 410, 420,430, and 440 in the series may comprise a corresponding furnace 411,421, 431, and 441, respectively, for heating reactor feed components toa desired temperature (e.g., to a temperature associated with a desiredreaction rate within a given reactor). Alternatively, one or morereactors 410, 420, 430, and 440 may share a common furnace wherepractical. All of the reactors 410, 420, 430, and 440, furnaces 411,421, 431, and 441, and associated piping may be referred to herein asthe aromatization zone.

The 1-hexene effluent 35, the auxiliary aromatization feed 37 (whenpresent), and optionally a raffinate stream 419 combine to form a mixedfeed stream 402 that flows into purification process 480. Purificationprocess 480 employs known processes to purify the mixed feed stream 402,which may include fractionation or other separation techniques, toremove impurities, such as oxygenates, sulfur, and/or metals. In anaspect, purification process 480 comprises a sulfur removal system. In afurther aspect, the sulfur removal system comprises a sulfur guard bed.Emanating from purification process 480 is a purified feed stream 403.The purified feed stream 403 optionally may be combined with a dryhydrogen recycle stream 465 to produce a hydrogen-rich purified feedstream 404. An oxygenate and/or nitrogenate stream 405 (i.e., O/Nstream) optionally may be combined with the hydrogen-rich purified feedstream 404 to produce an aromatization reactor feed stream 406. Theoxygenate and/or nitrogenate may be fed to the catalytic reactor systemat one or more locations in addition to the O/N stream 405 or as analternative to the O/N stream 405, as described in more detail herein.It is contemplated that some aspects of aromatization process 400 mayoperate without purification process 480, wherein the mixed feed stream402 continues directly into stream 403.

The aromatization reactor feed stream 406 is pre-heated in a firstfurnace 411, which heats the contents of feed stream 406 to a desiredtemperature, thereby producing a first aromatization reactor feed stream412. The first aromatization reactor feed stream 412 flows into a firstaromatization reactor 410, where it is contacted with an aromatizationcatalyst under suitable reaction conditions (e.g., temperature andpressure) that aromatize one or more components in the feed (e.g.,1-hexene), thereby increasing the arene content thereof. A firstaromatization reactor effluent stream 415 comprising arenes (e.g.,benzene), unreacted feed, and optionally other hydrocarbon compounds orbyproducts is recovered from the first aromatization reactor 410.

The first aromatization reactor effluent stream 415 is then pre-heatedin a second furnace 421, which heats the contents of stream 415 to adesired temperature, thereby producing a second aromatization reactorfeed stream 422. The second aromatization reactor feed stream 422 flowsinto a second aromatization reactor 420, where it is contacted with anaromatization catalyst under suitable reaction conditions foraromatizing one or more components in the feed (e.g., 1-hexene) toincrease the arene content thereof. A second aromatization reactoreffluent stream 425 comprising arenes (e.g., benzene), unreacted feed,and optionally other hydrocarbon compounds or byproducts is recoveredfrom the second aromatization reactor 420.

The second aromatization reactor effluent stream 425 is then pre-heatedin a third furnace 431, which heats the contents of stream 425 to adesired temperature, thereby producing a third aromatization reactorfeed stream 432. The third aromatization reactor feed stream 432 flowsinto a third aromatization reactor 430, where it is contacted with anaromatization catalyst under suitable reaction conditions foraromatizing one or more components in the feed (e.g., 1-hexene) toincrease the arene content thereof. A third aromatization reactoreffluent stream 435 comprising arenes (e.g., benzene), unreacted feed,and optionally other hydrocarbon compounds or byproducts is recoveredfrom the third aromatization reactor 430.

The third aromatization reactor effluent stream 435 is then pre-heatedin a fourth furnace 441, which heats the contents of stream 435 to adesired temperature, thereby producing a fourth aromatization reactorfeed stream 442. The fourth aromatization reactor feed stream 442 isthen fed into a fourth aromatization reactor 440, where it is contactedwith an aromatization catalyst under suitable reaction conditions foraromatizing one or more components in the feed (e.g., 1-hexene) toincrease the arene content thereof. A fourth aromatization reactoreffluent stream 445 comprising arenes (e.g., benzene), unreacted feed,and optionally other hydrocarbon compounds or byproducts is recoveredfrom the fourth aromatization reactor 440.

III.C.1.b. Downstream Processing

The fourth aromatization reactor effluent stream 445 flows into ahydrogen separation process 450 wherein a recovered hydrogen stream 455is separated from a first reformate stream 417. The first reformatestream 417 comprises the aromatization reaction products from reactors410, 420, 430, and 440; and optionally, aromatization reactionby-product(s) and/or side-product(s), unreacted feed, other hydrocarbonsor combinations thereof. In an aspect, the aromatization reactionside-products comprise toluene, xylene, ethylbenzene, diethylbenzene,mesitylene, hexamethylbenzene, or combinations thereof. The firstreformate stream 417 flows into a reformate purification process 470wherein a second reformate 477 is separated from a light reformateeffluent 472. In an aspect, the light reformate effluent 472 comprisesC⁵⁻ hydrocarbons. The second reformate 477 flows into apurification-extraction process 490 wherein a benzene effluent 45 isrecovered. The purification-extraction process 490 produces a raffinatestream 419 and, optionally, a stream comprising aromatization reactionby-product(s) and/or side-product(s). In an aspect, the raffinate stream419 may comprise benzene, toluene, xylene, branched alkanes, or acombination thereof. In an aspect, the raffinate stream 419 is recycledand combined with the mixed feed stream 402 as disclosed herein. Therecovered hydrogen stream 455 may be split from 0% to 100% between ahydrogen recycle stream 457 and a hydrogen effluent 41. In an aspect,the hydrogen effluent 41 may be combined with the first hydrogen feedstream 302 of FIG. 3 as disclosed herein. In a further aspect, thehydrogen effluent 41 may be routed to storage or for sale. A firstportion of the hydrogen recycle stream 457 is routed into a secondhydrogen feed 459. A second portion of the hydrogen recycle stream 457is dried in dryer 460, forming a dry hydrogen recycle stream 465thereby, which may be recycled into the purified feed stream 403 asdisclosed herein.

The second hydrogen feed 459 and the light reformate effluent 472comprising C⁵⁻ hydrocarbons enter C₂ recovery zone 485. In an aspect, C₂recovery zone 485 comprises a demethanizer; alternatively, adepropanizer; alternatively, a demethanizer upstream from adepropanizer, or alternatively, a demethanizer downstream from adepropanizer. A C₂ effluent 488 flows out of C₂ recovery zone 485. In anaspect, the C₂ effluent 488 comprises ethane, ethylene or a combinationthereof and may be combined with the hydrocarbon recycle stream 201 ofFIG. 2 , the ethylene recycle stream 306 of FIG. 3 , or both.

The hydrogen separation process 450 and purification-extraction process490 may be employed, for example as described in U.S. Pat. Nos.5,401,386; 5,877,367; and 6,004,452, each of which is incorporatedherein by reference in its entirety. For the sake of simplicity, FIG. 4does not illustrate the byproduct streams that are removed from thecatalytic reactor system at various points throughout the system.However, persons of ordinary skill in the art are aware of thecomposition and location of such byproduct streams. Also, while FIG. 4shows the O/N stream 405 being added to the hydrogen-rich purified feedstream 404, persons of ordinary skill in the art will appreciate thatthe oxygenate and/or nitrogenate may be added to any of streams 402,403, 404, 406, 412, 415, 417, 419, 422, 425, 432, 435, 442, 445, 455,465, 457, or combinations thereof.

III.C.2 Process Detail

In various aspects, the catalytic reactor system described herein maycomprise a fixed catalyst bed system, a moving catalyst bed system, afluidized catalyst bed system, or combinations thereof. In an aspect,the catalytic reactor system is a fixed bed system comprising one ormore fixed bed reactors. In a fixed bed system, the aromatizationreactor feed may be preheated in furnace tubes and passed into at leastone reactor that contains a fixed bed of the catalyst. The flow of thearomatization reactor feed can be upward, downward, or radially throughthe reactor. In various aspects, the catalytic reactor system describedherein may be operated as an adiabatic catalytic reactor system or anisothermal catalytic reactor system. As used herein, the term “catalyticreactor” and “reactor” refer interchangeably to the reactor vessel,reactor internals, and associated processing equipment, including butnot limited to the catalyst, inert packing materials, scallops, flowdistributors, center pipes, reactor ports, catalyst transfer anddistribution system, furnaces and other heating devices, heat transferequipment, and piping.

In an aspect, the catalytic reactor system is an aromatization reactorsystem comprising at least one aromatization reactor and itscorresponding processing equipment. As used herein, the terms“aromatization,” “aromatizing,” and “reforming” refer to the treatmentof a feed to provide an arene-enriched product wherein an arene contentof the product is greater than that of the feed. Typically, one or morecomponents of the feed undergo one or more reforming reactions toproduce arenes. Some of the reforming reactions that occur within thearomatization reactor system include dehydrocyclization reactions ofacyclic hydrocarbons to arenes (e.g., 1-hexene to benzene),dehydrogenation reactions of cyclohexanes to arenes,dehydroisomerization reactions of alkylcyclopentanes to arenes, orcombinations thereof. Depending upon the composition of the feed, anumber of other reactions may also occur, including dealkylationreactions of alkylbenzenes, isomerization reactions of paraffins,hydrocracking reactions that produce light gaseous hydrocarbons, e.g.,methane, ethane, ethylene, propane propylene, and butane, orcombinations thereof. Particular aspects of the integrated reformingsystems described herein utilize dehydrocyclization reactions of1-hexene, n-hexane or a combination thereof to produce benzene. In afurther aspect, the integrated reforming systems utilize dehydrogenationreactions of cyclohexane produce benzene.

In an aspect, the aromatization reaction occurs under process conditionsthat thermodynamically favor the dehydrocyclization reaction and limitundesirable hydrocracking reactions. Pressures within the reactor(s) maybe in a range of from about 0 psig to about 500 psig (about 0 MPag toabout 3.45 MPag), alternatively about 25 psig to about 300 psig (about0.17 MPag to about 2.07 MPag). The operating temperatures includereactor inlet temperatures in a range of from about 370° C. to about565° C., alternatively about 480° C. to about 540° C. A molar ratio ofhydrogen to hydrocarbons (e.g., 1-hexene) in the aromatization reactorfeed, may be in a range of from about 0.1:1 to about 20:1, alternativelyfrom about 1:1 to about 6:1.

III.C.2.a. Conversion & Selectivity

The aromatization reaction of the present disclosure may becharacterized by a conversion of 1-hexene to benzene based upon a totalamount-by-weight of 1-hexene fed to the aromatization reactor. In anaspect, the conversion of 1-hexene to benzene is greater than about 40wt. %; alternatively, greater than about 50 wt. %; alternatively,greater than about 60 wt. %; or alternatively, greater than about 70 wt.%.

The aromatization reaction of the present disclosure may becharacterized by a selectivity of 1-hexene to benzene based upon a totalamount-by-weight of 1-hexene converted in the aromatization reactor. Inan aspect, the selectivity of 1-hexene to benzene is greater than about50 wt. %; alternatively, greater than about 60 wt. %; alternatively,greater than about 70 wt. %; or alternatively, greater than about 75 wt.%.

III.C.3. Catalyst

Various types of aromatization catalysts may be used with the catalyticreactor system disclosed herein. In an aspect, the aromatizationcatalyst is a non-acidic catalyst that comprises an inorganic support, agroup VIII metal, and one or more halides. Suitable halides includechloride, fluoride, bromide, iodide, or combinations thereof. SuitableGroup VIII metals include iron, cobalt, nickel, ruthenium, rhodium,palladium, osmium, iridium, and platinum. Examples of catalysts suitablefor use with the catalytic reactor system described herein are theAROMAX® brand of catalysts available from the Chevron Phillips ChemicalCompany of The Woodlands, Tex., including the catalysts discussed inU.S. Pat. Nos. 7,932,425; 6,812,180; and 7,153,801, each of which isincorporated herein by reference in its entirety.

Inorganic supports for the aromatization catalyst of the presentdisclosure may generally include any inorganic oxide. These inorganicoxides include bound large pore aluminosilicates (zeolite supports),amorphous inorganic oxides and mixtures thereof. Large porealuminosilicates include, but are not limited to, L-zeolite, Y-zeolite,mordenite, omega zeolite, beta zeolite and the like. Amorphous inorganicoxides include, but are not limited to, aluminum oxide, silicon oxide,and titania. Suitable bonding agents for the inorganic oxides include,but are not limited to, silica, alumina, clays, titania, and magnesiumoxide.

In an aspect, the support is a bound potassium L-type zeolite, or KLzeolite. The term “KL zeolite” as used herein refers to L-type zeolitesin which the principal cation M incorporated in the zeolite ispotassium. A KL zeolite may be cation-exchanged or impregnated withanother metal and one or more halides to produce a platinum-impregnated,halided zeolite or a KL supported Pt-halide zeolite catalyst.

In an aspect, the Group VIII metal may be platinum. The platinum andoptionally one or more halides may be added to the zeolite support byany suitable method, for example via impregnation with a solution of aplatinum-containing compound and one or more halide-containingcompounds. For example, the platinum-containing compound can be anydecomposable platinum-containing compound. Examples of such compoundsinclude, but are not limited to, ammonium tetrachloroplatinate,chloroplatinic acid, diamineplatinum (II) nitrite,bis-(ethylenediamine)platinum (II) chloride, platinum (II)acetylacetonate, dichlorodiamine platinum, platinum (II) chloride,tetraamineplatinum (II) hydroxide, tetraamineplatinum chloride, andtetraamineplatinum (II) nitrate.

In a further aspect, the catalyst may be a large pore zeolite supportwith a platinum-containing compound and at least one organic ammoniumhalide compound. The organic ammonium halide compound may comprise oneor more compounds represented by the formula N(R)₄X, where X is a halideand where R represents a hydrogen or a substituted or unsubstitutedcarbon chain molecule having 1-20 carbons wherein each R may be the sameor different. In an aspect, R is selected from the group consisting ofmethyl, ethyl, propyl, butyl, and combinations thereof, morespecifically methyl. Examples of suitable organic ammonium compounds arerepresented by the formula N(R)₄X include ammonium chloride, ammoniumfluoride, and tetraalkylammonium halides such as tetramethylammoniumchloride, tetramethylammonium fluoride, tetraethylammonium chloride,tetraethylammonium fluoride, tetrapropylammonium chloride,tetrapropylammonium fluoride, tetrabutylammonium chloride,tetrabutylammonium fluoride, methyltriethylammonium chloride,methyltriethylammonium fluoride, and combinations thereof.

III.C.4. Oxygenate/Nitrogenate

In a particular aspect of the present disclosure, an oxygenate, anitrogenate, or both may be added to one or more process streams and/orcomponents in the catalytic reactor system. Not wishing to be limited bytheory, the oxygenate and/or nitrogenate (e.g., water) may be beneficialin activating, preserving, and/or increasing the productivity of certaintypes of aromatization catalysts as described in U.S. Pat. No.7,932,425. In an aspect, the 1-hexene effluent 35, the auxiliaryaromatization feed 37, and the optional raffinate recycle 419 aresubstantially free of sulfur, metals, and other known poisons foraromatization catalysts, and are initially substantially free ofoxygenates and nitrogenates. If present, such poisons can be removedusing methods known to those skilled in the art. In some aspects,1-hexene effluent 35, the auxiliary aromatization feed 37, and theoptional raffinate recycle 419 can be purified by first usingconventional hydrofining techniques, then using sorbents to remove theremaining poisons. Such hydrofining techniques and sorbents are includedin the purification process associated with the oxygenate and/ornitrogenate described below

As used herein, the term “oxygenate” refers to water or any chemicalcompound that forms water under catalytic aromatization conditions, suchas oxygen, oxygen-containing compounds, hydrogen peroxide, alcohols,ketones, esters, ethers, carbon dioxide, aldehydes, carboxylic acids,lactones, ozone, carbon monoxide or combinations thereof. In one aspect,water and/or steam is used as the oxygenate. In another aspect, oxygenmay be used as the oxygenate, wherein such oxygen converts to water insitu within one or more aromatization reactors under typicalaromatization conditions or within one or more hydrofining catalyst orsorbent beds under normal hydrofining conditions. Furthermore, theoxygenate may be any alcohol-containing compound. Specific examples ofsuitable alcohol-containing compounds are methanol, ethanol, propanol,isopropanol, butanol, t-butanol, pentanol, amyl alcohol, hexanol,cyclohexanol, phenol, or combinations thereof.

As used herein, the term “nitrogenate” refers to ammonia or any chemicalcompound that forms ammonia under catalytic aromatization conditionssuch as nitrogen, nitrogen-containing compounds, alkyl amines, aromaticamines, pyridines, pyridazines, pyrimidines, pyrazines, triazines,heterocyclic N-oxides, pyrroles, pyrazoles, imadazoles, triazoles,nitriles, amides, ureas, imides, nitro compounds, nitroso compounds, orcombinations thereof. While not wanting to be limited by theory, it isbelieved that the ammonia will improve catalyst activity in much thesame way as the water. Additionally, all the methods of addition andcontrol for oxygenates described herein can also be fully appliedadditionally or alternatively to the methods of addition and control fornitrogenates.

Those having ordinary skill in the art will appreciate that any of theoxygenates, nitrogenates, or mixtures thereof described herein may beused alone, in combination, or further combined to produce othersuitable oxygenates or nitrogenates. In some aspects, the oxygenate andnitrogenate may be contained within a single bifunctional compound. Theoxygenate and/or nitrogenate may be added in any suitable physical phasesuch as a gas, liquid, or combinations thereof. The oxygenate and/ornitrogenate may be added to one or more process streams and/orcomponents via any suitable means for their addition, for example apump, injector, sparger, bubbler, or the like. The oxygenate and/ornitrogenate may be introduced as a blend with a carrier. In someaspects, the carrier is hydrogen, a hydrocarbon, nitrogen, a noble gas,or mixtures thereof. In an aspect, the carrier is hydrogen. In a furtheraspect, the oxygenate and/or nitrogenate may be added at variouslocations within the aromatization process, at any time during theservice life of the aromatization catalyst, and in any suitable manner.In a still further aspect, the addition of oxygenate and/or nitrogenatefunctions to activate the aromatization catalyst, to increase the usefullife of the aromatization catalyst, to increase the selectivity and/orproductivity of the aromatization catalyst, and combinations thereof.

In an aspect, the existing oxygenate and/or nitrogenate content of astream to which the oxygenate and/or nitrogenate is to be added ismeasured and/or adjusted prior to addition of the oxygenate and/ornitrogenate. For example and with reference to FIG. 4 , one or more feedstreams such as the 1-hexene effluent 35, the auxiliary aromatizationfeed 37, the raffinate stream 419, the mixed feed stream 402, or the dryhydrogen recycle stream 465 may be measured for oxygenate and/ornitrogenate content and the oxygenate and/or nitrogenate content thereofadjusted prior to the addition of the oxygenate and/or nitrogenate.Likewise, the same streams may be measured for nitrogenate contentand/or the nitrogenate content thereof adjusted prior to the addition ofthe nitrogenate. Generally, a raw or untreated feed stream such as the1-hexene effluent 35 may contain some amount of oxygenate or nitrogenatewhen it flows into the catalytic reaction system described herein. Inaddition, depending on the plant configuration, the duration of feedstorage and weather conditions, the feed may absorb oxygenates ornitrogenates from the air. In order to accurately control the amount ofoxygenate or nitrogenates flowing into one or more of the aromatizationreactors (e.g., reactors 410, 420, 430, 440), the amount of oxygenateand/or nitrogenate in one or more feed streams to the reactors may bemeasured, adjusted, or both.

In an aspect, the oxygenate and/or nitrogenate content of a given streamsuch as a feed stream may be measured, for example with a real-time,in-line analyzer (not shown). In response to such measurement, theoxygenate and/or nitrogenate content of the stream may be adjusted bytreating and/or adding oxygenate and/or nitrogenate to the stream toobtain a desired amount of oxygenate and/or nitrogenate therein. In anaspect, a control loop links the analyzer to a treater and an oxygenateand/or nitrogenate injector such that the amount of oxygenate and/ornitrogenate in one or more streams is controlled in response to anoxygenate and/or nitrogenate set point for such streams. In an aspectthe measuring and/or adjusting of the oxygenate and/or nitrogenatecontent and associated equipment such as treaters and/or chemicalinjectors are included as part of the purification process 480. Theoxygenate and/or nitrogenate treaters vary based on the type and amountsof oxygenate and/or nitrogenate. In aspects where the oxygenatecomprises water, beds of sorbent materials may be used. These sorbentbeds are commonly known as driers. In aspects where the oxygenatecomprises oxygen, the use of treaters which convert the oxygen to watercan be used in combination with driers. In further aspects where thenitrogenate comprises a basic chemical, beds of sorbent materials may beused.

In an aspect, one or more streams such as the 1-hexene effluent 35, theauxiliary aromatization feed 37, the raffinate stream 419, the mixedfeed stream 402, or the dry hydrogen recycle stream 465 are treatedprior to the addition of oxygenate and/or nitrogenate thereto. In suchan aspect, measuring the oxygenate and/or nitrogenate content of thestreams before such treatment may optionally be omitted. If there is noapparatus for readily measuring the oxygenate and/or nitrogenate contentof the feed, then it is difficult to reliably maintain a desired levelin the aromatization reactors.

Treating one or more streams prior to the addition of the oxygenateand/or nitrogenate may aid in the overall control of the amount of waterand/or ammonia in one or more streams flowing into the aromatizationreactors by removing variability in the oxygenate and/or nitrogenatecontent in such streams. Treating such streams provides a consistent,baseline amount of oxygenate and/or nitrogenate in such streams for theaddition of oxygenate and/or nitrogenate to form an oxygenated streamsuch as the aromatization reactor feed stream 406. When the reactor feedis sufficiently free of oxygenates and/or nitrogenates, precisequantities of the oxygenate and/or nitrogenates can be added to thereactor feeds such that the amount of oxygenate and/or nitrogenates inthe reactors may be reliably maintained. In an aspect, purificationprocess 480 may include a hydrocarbon dryer that dries the feed streams(e.g., 1-hexene effluent 35), to a suitable moisture content. In otheraspects, purification process 480 may include a reduced copper bed or abed of triethyl aluminum on silica for use in removing oxygenates. Instill further aspects, the reduced copper bed or a bed of triethylaluminum on silica is used in combination with the hydrocarbon dryer.Similarly, dryer 460 can be used to dry the hydrogen recycle stream 457and/or other process streams (e.g., 1-hexene effluent 35), to a suitablemoisture content. In an aspect, a suitable oxygenate level in one ormore streams, such as the 1-hexene effluent 35, the auxiliaryaromatization feed 37, the raffinate stream 419, the mixed feed stream402, or the dry hydrogen recycle stream 465, is such that thecombination thereof produces a water concentration of less than about 1ppmv, alternatively less than about 0.5 ppmv, or alternatively less thanabout 0.1 ppmv in the untreated recovered hydrogen stream 455. In anaspect, one or more streams fed to the aromatization reactors, such asthe 1-hexene effluent 35, the auxiliary aromatization feed 37, theraffinate stream 419, the mixed feed stream 402, or the dry hydrogenrecycle stream 465, are substantially free of water following dryingthereof. In an aspect, the precise amount of the oxygenate and/or thenitrogenate may be added by partially or fully bypassing such treatmentprocesses. Alternatively, the precise amount of the oxygenate and/or thenitrogenate may be added by partially or fully running the hydrogenrecycle stream 457 through a wet, e.g. spent, mole sieve bed.

III.C.5. Effluent Composition

The benzene effluent 45 may comprise C₆ arenes. In an aspect, an amountof C₆ arenes in the benzene effluent 45 may be at least 60 wt. %;alternatively, at least 70 wt. %; alternatively, at least 75 wt. %;alternatively, at least 80 wt. %; alternatively, at least 85 wt. %; oralternatively, at least 90 wt. %, based upon a total weight of thebenzene effluent 45. In a further aspect, an amount of C₆ arenes in thebenzene effluent 45 may be in range of from about 60 wt. % to about 99.9wt. %; alternatively, from about 70 wt. % to about 99.8 wt. %;alternatively, from about 75 wt. % to about 99.7 wt. %; oralternatively, from about 80 wt. % to about 99.6 wt. %; oralternatively, from about 85 wt. % to about 99.6 wt. %. In a furtheraspect, an amount of benzene in the benzene effluent 45 may be at least85 wt. %; alternatively, at least 87.5 wt. % alternatively, at least 90wt. %; alternatively, at least 92.5 wt. %; alternatively, at least 95wt. %; alternatively, at least 97 wt. %; or alternatively, at least 98wt. %, wherein. In an aspect, the amount of benzene in the benzeneeffluent 45 may be in a range of from about 85 wt. % to about 99.9 wt.%; alternatively, about 87.5 wt. % to about 99.9 wt. %; alternatively,about 90 wt. % to about 99.9 wt. %; alternatively, about 92.5 wt. % toabout 99.9 wt. %; alternatively, about 95 wt. % to about 99.9 wt. %;alternatively, about 97 wt. % to about 99.9 wt. %; or alternatively,about 98 wt. % to about 99.9 wt. %.

III.D. Derivatization Process 500

Returning to FIG. 1 , the benzene effluent 45 may be routed for storageor for sale. In a further aspect, a portion of the benzene effluent 45is routed through a benzene feed 47 comprising benzene that flows intoderivatization process 500. In a further aspect, derivatization process500 comprises an ethylbenzene-styrene production process. Processes toproduce ethylbenzene and styrene from benzene are disclosed in U.S. Pat.Nos. 5,602,290; 5,880,320; 5,856,607; 6,252,126; and 6,790,342; each ofwhich is incorporated herein by reference in its entirety. It iscontemplated that derivatization process 500 may comprise a processother than the ethylbenzene-styrene production process.

III.D.1. Flowscheme

Referring to FIG. 5 , aspects of the derivatization process 500 aredescribed. The benzene feed 47 and an ethylene feed 27 flow intoalkylation zone 510. In an aspect, alkylation zone 510 comprises atleast one alkylation reactor. Benzene and ethylene are contacted with analkylation catalyst within alkylation zone 510 to produce an alkylationreactor effluent 515. Benzene, ethylene, and the alkylation catalyst maybe contacted in any manner suitable for the formation of ethylbenzene.In an aspect, the alkylation catalyst comprises a zeolite catalyst, anon-limiting example of which includes a ZSM-based zeolite. ZSM-basedzeolites are aluminosilicate zeolites having a chemical formula ofNa_(n)Al_(n)Si_(96-n)O₁₉₂·16H₂O where n is an integer from between 0 and27. In a further aspect, the ZSM-based zeolite may impart a selectivityof greater than 99% when used for the formation of ethylbenzene fromethylene and benzene.

In an aspect, the alkylation reactor effluent 515 comprises benzene andethylbenzene. The alkylation reactor effluent 515 flows into a firstseparation zone 520 wherein an ethylbenzene stream 525 comprisingethylbenzene is recovered. The first separation zone 520 furtherproduces a polyalkylated stream 527 and a benzene recycle stream 529.The first separation zone 520 may operate in any manner known to onehaving skill in the art and with the aid of the present disclosure. In afurther aspect, the first separation zone 520 comprises at least onefractionator. The polyalkylated stream 527 comprises C₁₀₊ arenesincluding, but not limited to, diethylbenzene and triethylbenzene. In anaspect, the polyalkylated stream 527 may be combined with thehydrocarbon recycle stream 201 of FIG. 2 as disclosed herein. Thebenzene recycle stream 529 is combined with the benzene feed 47.

The ethylbenzene stream 525 flows into dehydrogenation zone 530. In anaspect, dehydrogenation zone 530 comprises at least one dehydrogenationreactor. Within dehydrogenation zone 530 ethylbenzene is contacted witha dehydrogenation catalyst to produce a dehydrogenation reactor effluent535 and an efflux hydrogen stream 537. In an aspect, the dehydrogenationreactor effluent 535 comprises styrene. Ethylbenzene and thedehydrogenation catalyst may be contacted in any manner suitable for theformation of styrene. The dehydrogenation reactor effluent 535 flowsinto a second separation zone 540 to form a styrene effluent 51 and anaromatics stream 545. The second separation zone 540 may operate in anymanner known to one having skill in the art and with the aid of thepresent disclosure. In a further aspect, the second separation zone 540comprises at least one fractionator. The styrene effluent 51 may berouted for storage or for sale. The aromatics stream 545 may compriseC₆₊ arenes including, but not limited to, unreacted ethylbenzene and/orundesired products of the processes occurring in zones 510, 520 and/or530. In an aspect, the aromatics stream 545 may be combined (not shown),with the polyalkylated stream 527. In a further aspect, the aromaticsstream 545 may be combined (not shown), with the hydrocarbon recyclestream 201 of FIG. 2 as disclosed herein. In an aspect, the effluxhydrogen stream 537 may be combined with the first hydrogen feed stream302 of FIG. 3 or with the hydrogen effluent stream 41 of FIG. 1 , asdisclosed herein.

III.D.2. Effluent Composition

The styrene effluent 51 may comprise C₈ arenes wherein an amount of C₈arenes may be at least 60 wt. %; alternatively, at least 70 wt. %;alternatively, at least 75 wt. %; alternatively, at least 80 wt. %;alternatively, at least 85 wt. %; or alternatively, at least 90 wt. %,based upon a total weight of the styrene effluent 51. In a furtheraspect, an amount of C₈ arenes in the styrene effluent 51 may be inrange of from about 60 wt. % to about 99.9 wt. %; alternatively, fromabout 70 wt. % to about 99.8 wt. %; alternatively, from about 75 wt. %to about 99.7 wt. %; or alternatively, from about 80 wt. % to about 99.6wt. %; or alternatively, from about 85 wt. % to about 99.6 wt. %. In afurther aspect, an amount of styrene in the styrene effluent 51 may beat least 85 wt. %; alternatively, at least 87.5 wt. % alternatively, atleast 90 wt. %; alternatively, at least 92.5 wt. %; alternatively, atleast 95 wt. %; alternatively, at least 97 wt. %; or alternatively, atleast 98 wt. %. In a further aspect, the amount of styrene in thestyrene effluent 51 may be in a range of from about 85 wt. % to about99.9 wt. %; alternatively, about 87.5 wt. % to about 99.9 wt. %;alternatively, about 90 wt. % to about 99.9 wt. %; alternatively, about92.5 wt. % to about 99.9 wt. %; alternatively, about 95 wt. % to about99.9 wt. %; alternatively, about 97 wt. % to about 99.9 wt. %; oralternatively, about 98 wt. % to about 99.9 wt. %.

IV. Integrated Converting System 1100 with Hydrotreating Process

Referring to FIG. 6 , an integrated converting system 1100 is describedwherein like numbers represent like components described in relation toFIG. 1 . In contrast to FIG. 1 , integrated converting system 1100comprises hydrotreating process 110 connected between theoligomerization process 300 and the aromatization process 400. In anaspect, hydrotreating process 110 comprises at least one hydrogenationreactor. At least a portion of the 1-hexene comprising the 1-hexeneeffluent 35 flows into a hydrogenation reactor of hydrotreating process110 and is contacted with a hydrogenation catalyst to yield ahydrogenation reactor effluent. Within hydrotreating process 110, thehydrogenation reactor effluent passes through a purification stage (notshown), whereby a hexane effluent 115 comprising hexanes (e.g.,n-hexanes) is recovered. The hydrogenation catalyst may be contactedwith 1-hexenes in any manner suitable for the formation of hexanes.Further processes within hydrotreating process 110 (e.g.,fractionation), may impact the amounts of sulfur, nitrogen, and/oraromatic compounds which enter hydrotreating process 110, therebyreducing the amounts of sulfur, nitrogen, and/or aromatic compounds ofthe hexane effluent 115. In an aspect, hydrotreating process 110comprises a sulfur removal system. In an aspect, lower amounts ofsulfur, nitrogen, and/or aromatic compounds within a feedstock to thearomatization process 400 (e.g., the hexane effluent 115) may result inslower degradation and deactivation of the aromatization catalyst,leading to fewer plant turnarounds and greater aromatics selectivitythereby. In a further aspect, processes within hydrotreating process 110may enhance the cetane number, the density and/or the smoke point of thecomponents of the hexane effluent 115. In a further aspect, thearomatization auxiliary feed 37 flows into hydrotreating process 110.

In an aspect, the hexane effluent 115 comprises n-hexene. In a furtheraspect, an amount of n-hexane in the hexane effluent 115 may be at least85 wt. %; alternatively, at least 87.5 wt. % alternatively, at least 90wt. %; alternatively, at least 92.5 wt. %; alternatively, at least 95wt. %; alternatively, at least 97 wt. %; or alternatively, at least 98wt. %, based upon a total weight of the hexane effluent 115. In yet afurther, the amount of n-hexane in the hexane effluent 115 may be in arange of from about 85 wt. % to about 99.9 wt. %; alternatively, about87.5 wt. % to about 99.9 wt. %; alternatively, about 90 wt. % to about99.9 wt. %; alternatively, about 92.5 wt. % to about 99.9 wt. %;alternatively, about 95 wt. % to about 99.9 wt. %; alternatively, about97 wt. % to about 99.9 wt. %; or alternatively, about 98 wt. % to about99.9 wt. %. In an aspect, an amount of sulfur in the hexane effluent 115may be in a range of from about 0.01 ppm to about 5 ppm; oralternatively, about 0.05 to about 0.5 ppm. In an aspect, an amount ofnitrogen in the hexane effluent 115 may be in a range of from about 0.01ppm to about 5 ppm; or alternatively, about 0.05 to about 0.5 ppm. In anaspect, an amount of aromatic components in the hexane effluent 115 maybe in a range of from about 0.01 ppm to about 1 ppm; or alternatively,about 0.02 to about 0.2 ppm. The ppm values are weight-weight valuesbased upon the total weight of the hexane effluent 115.

Referring to FIG. 6 , the hexane effluent 115 flows into aromatizationprocess 400 in place of the 1-hexene effluent 35. In an aspect,aromatization process 400 of integrated converting system 1100 comprisesan aromatization reactor system wherein hexanes (e.g., n-hexane), arecontacted with an aromatization catalyst to produce benzene. All otherfunctions and components (e.g., benzene effluent 45), of aromatizationprocess 400 of integrated converting system 1100 operate in a mannersimilar to aromatization process 400 of integrated converting system1000 as disclosed herein.

V. Integrated Converting System 1200 with Cyclohexane Production

Referring to FIG. 7 , an integrated converting system 1200 is describedwherein like numbers represent like components described in relation toFIG. 6 . In contrast to FIG. 6 , integrated converting system 1200 isabsent derivatization process 500 (also can be referred to as anethylbenzene-styrene production process), as well as the ethylene feed27 and the styrene effluent 51 associated therewith. Within integratedconverting system 1200, a cyclohexane recycle stream 123 flows intooligomerization process 300 wherein cyclohexane functions as a solvent(i.e., diluent). In an aspect, the cyclohexane recycle stream 123 iscombined with the solvent feed 308 of FIG. 3 as disclosed herein. Thecyclohexane recycle stream 123 comprises a portion of a cyclohexaneeffluent 125 which flows out of benzene hydrogenation process 120, asfurther described herein. A mixed C₆ effluent 31 flows out ofoligomerization process 300 of integrated converting system 1200. In anaspect, the mixed C₆ effluent 31 comprises 1-hexene and cyclohexane. Themixed C₆ effluent 31 flows into hydrotreating process 110 to produce amixed hexane effluent 117. In an aspect, the mixed hexane effluent 117comprises hexanes (e.g., n-hexanes) and cyclohexane. The hexane effluent117 flows into aromatization process 400 wherein hexanes (e.g.,n-hexanes) and cyclohexane are converted in benzene. A portion of thebenzene effluent 45 is routed through the benzene feed 47 and a portionof the hydrogen effluent 41 is routed through a reducing feed 43. Thebenzene feed 47 and the reducing feed 43 flow into benzene hydrogenationprocess 120 wherein hydrogenation of benzene produces a cyclohexaneeffluent 125. In an aspect, at least a portion of the cyclohexaneeffluent 125 comprises cyclohexane and may be routed for storage or forsale. Hydrogenation of benzene may be performed by any means suitable asdetermined by one having ordinary skill in the art and with the aid ofthis disclosure. For example, a hydrogenation catalyst can be utilized.Operating conditions within hydrogenation process 120 may be anycombination of conditions suitable as determined by one having ordinaryskill in the art and with the aid of this disclosure. In an aspect, thetemperature and pressure within hydrogenation process 120 may be atlevels capable to hydrogenate benzene. In a further aspect,hydrogenation process 120 may have a temperature in a range of fromabout 10° C. to about 205° C. In yet a further aspect, hydrogenationprocess 120 may have a pressure in a range of about from 360 psig toabout 615 psig (about 2.48 MPag to about 4.24 MPag).

In an aspect, an amount of cyclohexane in the cyclohexane effluent 125may be at least 85 wt. %; alternatively, at least 87.5 wt. %alternatively, at least 90 wt. %; alternatively, at least 92.5 wt. %;alternatively, at least 95 wt. %; alternatively, at least 97 wt. %; oralternatively, at least 98 wt. %, based upon a total weight of thecyclohexane effluent 125. In yet a further aspect, the amount ofcyclohexane in the cyclohexane effluent 125 may be in a range of fromabout 85 wt. % to about 99.9 wt. %; alternatively, about 87.5 wt. % toabout 99.9 wt. %; alternatively, about 90 wt. % to about 99.9 wt. %;alternatively, about 92.5 wt. % to about 99.9 wt. %; alternatively,about 95 wt. % to about 99.9 wt. %; alternatively, about 97 wt. % toabout 99.9 wt. %; or alternatively, about 98 wt. % to about 99.9 wt. %.

VI. Integrated Converting System 1300 with High Purity 1-Hexene Effluent

Referring to FIG. 8 , an integrated converting system 1300 is describedwherein like numbers represent like components described in relation toFIG. 7 . Flowing out of oligomerization process 300 of integratedconverting system 1300 is a lower purity 1-hexene (LPH) stream 33. In anaspect, the LPH stream 33 comprises 1-hexene and cyclohexane. A firstportion of the LPH stream 33 flows into hydrotreating process 110 toproduce the mixed hexane effluent 117 that flows into aromatizationprocess 400. A second portion of the LPH stream 33 is routed through amixed C₆ feed 32 which flows into C₆ separator 130. Within C₆ separator130 the mixed C₆ feed 32 is separated into a higher purity 1-hexene(HPH) stream 135 and a solvent recycle stream 132. The HPH stream 135may be routed for storage or for sale. In an aspect, the HPH stream 135may be used in a polymerization process or in an oligomerization processnot associated with an integrated converting system of the presentdisclosure. In an aspect, the solvent recycle stream 132 may be combinedwith the cyclohexane recycle stream 123; or alternatively, with thesolvent feed 308 of FIG. 3 as described herein. The C₆ separator 130 mayoperate in any manner suitable for producing the HPH stream 135 and thesolvent recycle stream 132. In an aspect, C₆ separator 130 comprises atleast one fractionator.

In an aspect, the HPH stream 135 comprises 1-hexene. In a furtheraspect, an amount of 1-hexene in the HPH stream 135 may be at least 85wt. %; alternatively, at least 87.5 wt. % alternatively, at least 90 wt.%; alternatively, at least 92.5 wt. %; alternatively, at least 95 wt. %;alternatively, at least 97 wt. %; alternatively, at least 98 wt. % oralternatively, at least 99 wt. %, based upon a total weight of C₆hydrocarbons in the HPH stream 135. In yet a further, the amount of1-hexene in the HPH stream 135 may be in a range of from about 85 wt. %to about 99.9 wt. %; alternatively, about 87.5 wt. % to about 99.9 wt.%; alternatively, about 90 wt. % to about 99.9 wt. %; alternatively,about 92.5 wt. % to about 99.9 wt. %; alternatively, about 95 wt. % toabout 99.9 wt. %; alternatively, about 97 wt. % to about 99.9 wt. %; oralternatively, about 98 wt. % to about 99.9 wt. %.

VII. Integrated Converting System 1400 with High Purity 1-HexeneEffluent & Ethylene Split

Referring to FIG. 9 , an integrated converting system 1400 is describedwherein like numbers represent like components described in relation toFIG. 8 . Prior to flowing into cracking process 200 the hydrocarbonfeedstock 10 is combined with an ethane split stream 162, as furtherdisclosed herein. A portion of the cracking process effluent 25 isrouted through a utility ethylene stream 29 which flows into C₂separator 160. The utility ethylene stream 29 within C₂ separator 160 isseparated into an ethylene split stream 165 and the ethane split stream162. In an aspect, the ethylene split stream 165 may be combined withthe ethylene recycle stream 306 of FIG. 3 as disclosed herein. In afurther aspect, the ethylene split stream 165 may be used in apolymerization process or in an oligomerization process not associatedwith an integrated converting system of the present disclosure. In yet afurther aspect, the ethylene split stream 165 may be routed for storageor for sale. The C₂ separator 160 may operate in any manner suitable forproducing the ethylene split stream 165 and the ethane split stream 162.In an aspect, C₂ separator 160 comprises at least one fractionator.

In an aspect, the ethylene split stream 165 comprises ethylene. In afurther aspect, an amount of ethylene in the ethylene split stream 165may be at least 85 wt. %; alternatively, at least 87.5 wt. %alternatively, at least 90 wt. %; alternatively, at least 92.5 wt. %;alternatively, at least 95 wt. %; alternatively, at least 97 wt. %; oralternatively, at least 98 wt. %, based upon a total weight of theethylene split stream 165. In yet a further, the amount of ethylene inthe ethylene split stream 165 may be in a range of from about 85 wt. %to about 99.9 wt. %; alternatively, about 87.5 wt. % to about 99.9 wt.%; alternatively, about 90 wt. % to about 99.9 wt. %; alternatively,about 92.5 wt. % to about 99.9 wt. %; alternatively, about 95 wt. % toabout 99.9 wt. %; alternatively, about 97 wt. % to about 99.9 wt. %; oralternatively, about 98 wt. % to about 99.9 wt. %.

In an aspect, the ethane split stream 162 comprises ethane. In a furtheraspect, an amount of ethane in the ethane split stream 162 may be atleast 85 wt. %; alternatively, at least 87.5 wt. % alternatively, atleast 90 wt. %; alternatively, at least 92.5 wt. %; alternatively, atleast 95 wt. %; alternatively, at least 97 wt. %; or alternatively, atleast 98 wt. %, based upon a total weight of the ethane split stream162. In yet a further, the amount of ethane in the ethane split stream162 may be in a range of from about 85 wt. % to about 99.9 wt. %;alternatively, about 87.5 wt. % to about 99.9 wt. %; alternatively,about 90 wt. % to about 99.9 wt. %; alternatively, about 92.5 wt. % toabout 99.9 wt. %; alternatively, about 95 wt. % to about 99.9 wt. %;alternatively, about 97 wt. % to about 99.9 wt. %; or alternatively,about 98 wt. % to about 99.9 wt. %.

VIII. Integrated Converting System 1500 with High Purity 1-HexeneEffluent & Raffinate

Referring to FIG. 10 , an integrated converting system 1500 is describedwherein like numbers represent like components described in relation toFIG. 8 . In contrast to FIG. 8 , integrated converting system 1500 isabsent benzene hydrogenation process 120 as well as the reducing feed43, the benzene feed 47, the cyclohexane recycle stream 123 and thecyclohexane effluent 125 associated therewith. Flowing intooligomerization process 300 of integrated converting system 1500 is theraffinate stream 419 recovered from purification-extraction process 490of FIG. 4 as disclosed herein. The raffinate stream 419 is combined withthe solvent feed 308 of FIG. 3 wherein one or more components of theraffinate stream 419 may function as a solvent (i.e., diluent) withinoligomerization process 300. In an aspect, benzene, toluene, xylene,branched alkanes, or a combination thereof may function as a solvent(i.e., diluent) within oligomerization process 300. The lower purity1-hexene stream 33 flows out of oligomerization process 300 andintegrated converting system 1500 continues as disclosed in relation toFIG. 8 .

IX. Integrated Converting System 1600 with Deeper Integration

Referring to FIG. 11 , an integrated converting system 1600 is describedwherein like numbers represent like components described in relation toFIG. 1 . In contrast to FIG. 1 , integrated converting system 1600 isabsent derivatization process 500 (i.e., ethylbenzene-styrene productionprocess), as well as the ethylene feed 27, the benzene feed 47 and thestyrene effluent 51 associated therewith. Within integrated convertingsystem 1600, the hydrocarbon feedstock 10 flows into cracking process290 which operates in a manner similar to cracking process 200 of FIG. 2, unless otherwise explicitly disclosed. A cracking feed 141 flows intocracking process 290. In an aspect, the cracking feed 141 is combinedwith the hydrocarbon recycle stream 201 of FIG. 2 .

Flowing out of cracking process 290 are the cracking process effluent25, a light hydrocarbons stream 146, a crude pyrolysis gasoline (CPG)stream 142, a fuel gas stream 144, and a steam effluent 148. The lighthydrocarbons stream 146 may be recovered from the cracker effluent 210,the C₃₊ stream 262, and/or the alternate C₃₊ stream 282 of FIG. 2 . Inan aspect, the light hydrocarbons stream 146 comprises lighthydrocarbons produced with cracking process 290 wherein the lighthydrocarbons comprise methane, ethane, ethylene, propane, propylene,butane, or combinations thereof. A first portion 146 a of the lighthydrocarbons stream 146 is routed into oligomerization process 300 andis used for cooling and/or refrigeration therein. A second portion 146 bof the light hydrocarbons stream 146 enters aromatization process 400and is used for cooling and/or refrigeration therein. The steam effluent148 comprises steam recovered from cracking process 290 (e.g., crackingzone 205), of FIG. 2 . The steam effluent 148 flows into oligomerizationprocess 300 and serves as a heat source therein. The CPG stream 142flows into aromatization process 400 and may be routed to the firstreformate stream 417 of FIG. 4 . The fuel gas stream 144 entersaromatization process 400. Flowing out of oligomerization process 300 isthe heavies effluent 336 of FIG. 3 which, in an aspect, may be combinedwith the cracking feed 141. Flowing out of aromatization process 400 isthe cracking feed 141 which, in an aspect, may be combined with theraffinate stream 419 of FIG. 4 .

IX.A. MOGAS Processing

Disclosed herein is a method of enriching a motor fuel stream (i.e.,mogas). In an aspect, the mogas comprises the fuel gas stream 144 ofintegrated converting system 1600. In a further aspect, the mogas is anenriched motor fuel. In a particular aspect, the mogas is enriched byblending therein one or more of the effluent streams generated by anintegrated converting system of the present disclosure. For example, theheavies effluent 336, the raffinate stream 419, or a combination thereofmay be blended into the mogas.

Described herein is a limited set of operating conditions (e.g.,temperature, pressure) for the processes and systems of the presentdisclosure. One having ordinary skill in the art will appreciate thatoperating conditions which are not presently disclosed may have anyvalue or, alternatively, range of values, suitable for operation of theprocesses and systems as disclosed herein. In a further aspect, changesto operating conditions within any of the processes and systemsdisclosed herein may be implemented by one having ordinary skill in theart with the aid of the present disclosure to maintain operation of theprocesses and systems disclosed.

X. Advantages

In an aspect, producing benzene with an integrated converting system ofthe present disclosure can be advantageous in one or more areas whencompared to conventional methods of benzene production that utilizenon-integrated (i.e., stand-alone) converting processes. Conventionalmethods of benzene production utilize materials contained in crude oil(e.g., cracking of naphtha) such that the cost of benzene production islinked to crude oil. The present disclosure utilizes ethane contained innatural gas as a starting material (e.g., stream cracking of ethane)such that the cost of benzene production is advantageously decoupledfrom crude oil. As increasing quantities of natural gas becomeavailable, the price of natural gas is decreasing while other factorsare increasing demand for benzene. For example, in North America anabundance of ethane for steam cracking has made naphtha crackinguneconomical. There also appears to be the possibility of a potentiallysignificant oversupply of ethylene in the future. A further advantage isthat ethylene can be converted into benzene with an integratedconverting system of the present disclosure as the market dictates.Also, a further advantage is that ethylbenzene or styrene production canbe increased or decreased as the market dictates.

FIG. 12 illustrates a comparison of the price of ethylene with the priceof benzene on a carbon basis. Data used for creating the graph of FIG.12 was obtained from IHS Chemical Market Advisory Service. FIG. 12illustrates how the price of benzene has risen with respect to ethyleneover the past 20+ years and would be expected to continually rise in thefuture. A further advantage of converting ethylene into benzene with anintegrated converting system of the present disclosure is the ability totake advantage of the price difference between ethylene and benzene.

A further advantage of an integrated converting system of the presentdisclosure is the ability to produce large quantities of ethylene,1-hexene, benzene and styrene and sell portions of each as global demanddictates. An integrated converting system of the present disclosurefeatures flexible modification of the rates of production of the productstreams to accommodate changes in demand and/or prices of 1-hexene,benzene, and styrene. In an aspect, as much as 1.5 million tons ofethylene could be produced annually. Other products that can begenerated for sale by utilizing an integrated converting system of thepresent disclosure include hydrogen (i.e., hydrogen effluent 41),styrene (i.e., styrene effluent 51), and cyclohexane (i.e., cyclohexaneeffluent 125).

A further advantage of an integrated converting system of the presentdisclosure is that 1-hexene may potentially be used as a feed for thearomatization process. Hydrogenation of 1-hexene to n-hexane asdisclosed herein might provide further advantages including slowercatalyst deactivation, fewer plant turnarounds, and greater aromaticsselectivity. Because the cracking feedstock is derived from natural gasinstead of crude oil the 1-hexene/n-hexane being fed to thearomatization process would have a low sulfur content, potentiallyallowing for the removal of traditional staged combustion airpretreaters and the subsequent lowering of capital cost.

A further advantage of an integrated converting system of the presentdisclosure is use of light hydrocarbons produced with cracking process200 in the refrigeration of oligomerization process 300. This approachwould allow removal of dedicated refrigeration units withinoligomerization process 300 and provide a subsequent lowering of capitalcost. A further advantage is that cracking process 200 may producehydrogen and methane (not shown) which can be used as fuel for heatingand/or operating other process within the integrated converting system.This may allow for design improvements to a plant or system such asdownsizing heat exchangers.

EXAMPLES

The subject matter having been generally described, the followingexamples are given as particular aspects of the disclosure and todemonstrate the practice and advantages thereof. It is understood thatthe examples are given by way of illustration and are not intended tolimit the specification of the claims to follow in any manner. It is tobe clearly understood that resort can be had to various other aspects,modifications, and equivalents thereof which, after reading thedescription herein, can be suggest to one of ordinary skill in the artwithout departing from the spirit of the present disclosure or the scopeof the appended claims.

FIGS. 13 and 14 display results for utilization of an AROMAX® catalystto produce benzene from 1-hexene. Operating conditions were at aconstant temperature of 950° F. (510° C.), a liquid hourly spacevelocity of 12 h⁻¹, a pressure of 100 psig (0.68 MPag), and a molarratio of hydrogen to hydrocarbons of 1.2:1. FIG. 13 shows that under theconditions specified conversion for 1-hexene to benzene approachesnearly 100% at around 5 hours. FIG. 14 shows that under the conditionsspecified, the selectivity for converting 1-hexene to benzene remains atabout 85% at around 5 hours. After about 1 hour, the benzene selectivityat the above conditions is approximately 80%.

ADDITIONAL DISCLOSURE

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present disclosure. Thus, the claims are a further description andare an addition to the detailed description of the present disclosure.The disclosures of all patents, patent applications, and publicationscited herein are hereby incorporated by reference.

Aspects of methods and systems have been described. The following areaspects of non-limiting, specific embodiments in accordance with thepresent disclosure:

In Aspect 1, the techniques described herein relate to a methodincluding: contacting, in an oligomerization reactor, ethylene and anoligomerization catalyst to yield an oligomerization reactor effluentincluding 1-hexene; recovering 1-hexene from the oligomerization reactoreffluent; and contacting, in an aromatization reactor, the 1-hexenerecovered from the oligomerization reactor effluent with anaromatization catalyst to yield an aromatization reactor effluentincluding benzene.

In Aspect 2, the techniques described herein relate to the method ofAspect 1, further including: cracking ethane, propane, butane, pentane,naphtha, or mixtures thereof in a steam cracker to yield a crackereffluent including ethylene; and flowing ethylene recovered from thecracker effluent to the oligomerization reactor.

In Aspect 3, the techniques described herein relate to the method ofAspect 2, further including: recovering light hydrocarbons from thecracker effluent; and using the light hydrocarbons recovered from thecracker effluent for cooling for an oligomerization process containingthe oligomerization reactor or for an aromatization process containingthe aromatization reactor.

In Aspect 4, the techniques described herein relate to the method ofAspect 2 or 3, further including: recovering steam from the steamcracker; and using the steam recovered from the steam cracker in anoligomerization process containing the oligomerization reactor.

In Aspect 5, the techniques described herein relate to the method any ofAspects 2 to 4, further including: flowing ethylene recovered from thecracker effluent to an alkylation reactor; flowing benzene recoveredfrom the aromatization reactor effluent to the alkylation reactor; andcontacting, in the alkylation reactor, the ethylene recovered from thecracker effluent and the benzene recovered from the aromatizationreactor effluent with an alkylation catalyst to yield an alkylationreactor effluent including ethylbenzene.

In Aspect 6, the techniques described herein relate to the method ofAspect 5, further including: flowing ethylbenzene recovered from thealkylation reactor effluent to a dehydrogenation reactor; andcontacting, in the dehydrogenation reactor, ethylbenzene with adehydrogenation catalyst to yield a dehydrogenation reactor effluentincluding styrene.

In Aspect 7, the techniques described herein relate to the method of anyof Aspects 1 to 6, further including: flowing at least a portion of1-hexene recovered from the oligomerization reactor effluent to ahydrogenation reactor; contacting, in the hydrogenation reactor, the atleast a portion of 1-hexene with a hydrogenation catalyst to yield ahydrogenation reactor effluent including hexanes; recovering hexanesfrom the hydrogenation reactor effluent; and contacting, in thearomatization reactor, hexanes recovered from the hydrogenation reactoreffluent with the aromatization catalyst to yield the aromatizationreactor effluent including benzene.

In Aspect 8, the techniques described herein relate to the method of anyof Aspects 1 to 7, wherein the step of contacting ethylene and anoligomerization catalyst is performed in the presence of a diluentselected from the group consisting of isobutane, cyclohexane,methylcyclohexane, n-alkanes, branched alkanes, iso-paraffin solvents,2,2,4-trimethylpentane, and combinations thereof.

In Aspect 9, the techniques described herein relate to the method of anyof Aspects 1 to 8, wherein the 1-hexene is recovered from theoligomerization reactor effluent by washing to remove catalyst andfractionation to remove diluent.

In Aspect 10, the techniques described herein relate to the method ofany of Aspects 1 to 9, wherein the oligomerization catalyst includes achromium source, a pyrrole-containing compound, and a metal alkyl,optionally supported on an inorganic oxide support; and wherein thearomatization catalyst includes a zeolite support, a group VIII metal,and one or more halides.

In Aspect 11, the techniques described herein relate to the method ofany of Aspects 1 to 10, wherein a conversion of 1-hexene to benzene isgreater than about 70 wt. % based on a total amount of 1-hexene fed tothe aromatization reactor.

In Aspect 12, the techniques described herein relate to the method ofany of Aspects 1 to 11, wherein a selectivity of 1-hexene to benzene isgreater than about 75 wt. % based on a total weight of 1-hexeneconverted in the aromatization reactor.

In Aspect 13, the techniques described herein relate to the method ofany of Aspects 1 to 12, further including: contacting, in ahydrogenation reactor, benzene recovered from the aromatization reactoreffluent with a hydrogenation catalyst to yield hydrogenation reactoreffluent including cyclohexane; recovering cyclohexane from thehydrogenation reactor effluent; and recycling cyclohexane recovered fromthe hydrogenation reactor effluent to the oligomerization reactor.

In Aspect 14, the techniques described herein relate to the method ofany of Aspects 1 to 13, further including: recovering a lower purity1-hexene stream from the oligomerization reactor effluent; recovering ahigher purity 1-hexene stream from the lower purity 1-hexene stream; andflowing a portion of the lower purity 1-hexene stream to a hydrogenationreactor.

In Aspect 15, the techniques described herein relate to the method ofany of Aspects 1 to 14, wherein a sulfur removal system is not used inthe step of flowing 1-hexene recovered from the oligomerization reactoreffluent to the aromatization reactor.

In Aspect 16, the techniques described herein relate to the method ofany of Aspects 1 to 15, wherein the step of contacting ethylene and anoligomerization catalyst is performed in the presence of a diluentrecovered from the aromatization reactor effluent, wherein the diluentis selected from a raffinate, benzene, toluene, xylene, branchedalkanes, or a combination thereof.

In Aspect 17, the techniques described herein relate to the method ofany of Aspects 1 to 16, wherein the oligomerization reactor effluentfurther includes heavy hydrocarbons having greater than 8 carbon atoms,the method further including: flowing the heavy hydrocarbons recoveredfrom the oligomerization reactor effluent to a steam cracker; andcracking the heavy hydrocarbons in the steam cracker.

In Aspect 18, the techniques described herein relate to the method ofany of Aspects 1 to 17, further including: flowing a raffinate recoveredfrom the aromatization reactor effluent to a steam cracker; and crackingthe raffinate in the steam cracker.

In Aspect 19, the techniques described herein relate to the method ofany of Aspects 1 to 18, wherein the oligomerization reactor effluentfurther includes a heavy hydrocarbon having greater than 8 carbon atoms,the method further including: blending the heavy hydrocarbon, araffinate obtained from the aromatization reactor effluent, or both theheavy hydrocarbon and the raffinate into a motor fuel stream.

In Aspect 20, the techniques described herein relate to the method ofany of Aspects 1 to 19, further including: flowing hydrogen and lighthydrocarbons having less than 6 carbon atoms recovered from thearomatization reactor effluent to a demethanizer, a depropanizer, orboth a demethanizer and a depropanizer.

In Aspect 21, the techniques described herein relate to the method ofany of Aspects 1 to 20, wherein the ethylene is fed to theoligomerization reactor in a stream including ethylene and ethane.

In Aspect 22, the techniques described herein relate to a systemincluding: an oligomerization reactor configured to contact ethylenewith an oligomerization catalyst to yield an oligomerization reactoreffluent including 1-hexene; and an aromatization reactor configured tocontact 1-hexene recovered from the oligomerization reactor effluentwith an aromatization catalyst to yield an aromatization reactoreffluent including benzene.

In Aspect 23, the techniques described herein relate to the system ofAspect 22, wherein a conversion of 1-hexene to benzene in thearomatization reactor is greater than about 70 wt. % based on a totalweight of 1-hexene fed to the aromatization reactor.

In Aspect 24, the techniques described herein relate to the system ofAspect 22 or 23, wherein a selectivity of 1-hexene to benzene in thearomatization reactor is greater than about 75 wt. % based on a totalweight of 1-hexene converted in the aromatization reactor.

In Aspect 25, the techniques described herein relate to the system ofany of Aspects 22 to 24, further including: a steam cracker to yield acracker effluent including ethylene, wherein the oligomerization reactoris configured to receive ethylene recovered from the cracker effluentfor oligomerization in the oligomerization reactor.

In Aspect 26, the techniques described herein relate to the systemAspect 25, further including: an alkylation reactor configured tocontact benzene recovered from the aromatization reactor effluent andethylene recovered from the steam cracker with an alkylation catalyst toproduce an alkylation reactor effluent including ethylbenzene.

In Aspect 27, the techniques described herein relate to the system ofAspect 26, further including: a dehydrogenation reactor configured tocontact ethylbenzene recovered from the alkylation reactor effluent witha dehydrogenation catalyst to produce a dehydrogenation reactor effluentincluding styrene.

In Aspect 28, the techniques described herein relate to the system ofany of Aspects 25 to 27, wherein the cracker effluent further includeslight hydrocarbons, wherein an oligomerization process containing theoligomerization reactor, an aromatization process containing thearomatization reactor, or both the oligomerization process and thearomatization process are configured to receive at least a portion ofthe light hydrocarbons.

In Aspect 29, the techniques described herein relate to the system ofany of Aspects 25 to 28, wherein the steam cracker is configured toproduce steam, wherein an oligomerization process containing theoligomerization reactor is configured to receive steam recovered fromthe steam cracker.

In Aspect 30, the techniques described herein relate to the system ofany of Aspects 22 to 29, wherein the oligomerization catalyst includes achromium source, a pyrrole-containing compound, and a metal alkyl,optionally supported on an inorganic oxide support; and wherein thearomatization catalyst includes a zeolite support, a group VIII metal,and one or more halides.

In Aspect 31, the techniques described herein relate to a system thatincludes: an oligomerization reactor configured to contact ethylene withan oligomerization catalyst to yield an oligomerization reactor effluentincluding 1-hexene; a hydrogenation reactor configured to contact1-hexene recovered from the oligomerization reactor effluent with ahydrogenation catalyst to yield an aromatization feed including hexane;and an aromatization reactor configured to contact the aromatizationfeed with an aromatization catalyst to yield an aromatization reactoreffluent including benzene.

In Aspect 32, the techniques described herein relate to the system ofAspect 31, further including: a steam cracker to yield a crackereffluent including ethylene, wherein the oligomerization reactor isconfigured to receive ethylene recovered from the cracker effluent foroligomerization in the oligomerization reactor.

In Aspect 33, the techniques described herein relate to the system ofAspect 32, further including: an alkylation reactor configured tocontact benzene recovered from the aromatization reactor effluent andethylene recovered from the steam cracker with an alkylation catalyst toproduce an alkylation reactor effluent including ethylbenzene.

In Aspect 34, the techniques described herein relate to the system ofAspect 35, further including: a dehydrogenation reactor configured tocontact ethylbenzene recovered from the alkylation reactor effluent witha dehydrogenation catalyst to produce a dehydrogenation reactor effluentincluding styrene.

In Aspect 35, the techniques described herein relate to the system ofany of Aspects 31 to 34, wherein the aromatization reactor is furtherconfigured to produce a hydrogen effluent, the system further including:a second hydrogenation reactor configured to contact benzene recoveredfrom the aromatization reactor effluent and hydrogen recovered from thehydrogen effluent with a second hydrogenation catalyst to produce asecond hydrogenation reactor effluent including cyclohexane, wherein theoligomerization reactor is configured to receive at least a portion ofthe cyclohexane from the second hydrogenation reactor effluent.

In Aspect 36, the techniques described herein relate to the system ofany of Aspects 31 to 35, wherein the oligomerization reactor effluentincludes a lower purity 1-hexene stream, the system further including: aC6 separator configured to recover a higher purity 1-hexene stream froma first portion the lower purity 1-hexene stream, wherein thehydrogenation reactor is configured to receive a second portion of thelower purity 1-hexene stream.

In Aspect 37, the techniques described herein relate to the system ofany of Aspects 31 to 36, further including: a steam cracker to yield acracker effluent including ethylene, wherein the oligomerization reactoris configured to receive ethylene recovered from the cracker effluentfor oligomerization in the oligomerization reactor; and a C2 separatorconfigured to separate a portion of the cracker effluent into ethyleneand ethane, wherein the steam cracker is configured to receive ethanerecovered from the C2 separator.

In Aspect 38, the techniques described herein relate to the system ofany of Aspects 31 to 37, wherein the oligomerization reactor isconfigured to receive a raffinate from the aromatization reactor,wherein the raffinate includes benzene, toluene, xylene, branchedalkanes, or a combination thereof, wherein the oligomerization reactoreffluent includes a lower purity 1-hexene stream, the system furtherincluding: a C6 separator configured to recover a higher purity 1-hexenestream from a first portion the lower purity 1-hexene stream, whereinthe hydrogenation reactor is configured to receive a second portion ofthe lower purity 1-hexene stream.

In Aspect 39, the techniques described herein relate to the system ofany of Aspects 31 to 38, wherein the oligomerization catalyst includes achromium source, a pyrrole-containing compound, and a metal alkyl,optionally supported on an inorganic oxide support; and wherein thearomatization catalyst includes a zeolite support, a group VIII metal,and one or more halides.

While several aspects and embodiments of the present disclosure havebeen shown and described, modifications thereof can be made by oneskilled in the art without departing from the spirit and teachings ofthe present disclosure. The aspects, embodiments, and examples describedherein are exemplary only, and are not intended to be limiting. Manyvariations and modifications of the present disclosure are possible andare within the scope of the subject matter.

Regarding claim transitional terms or phrases, the transitional term“comprising,” which is synonymous with “including,” “containing,”“having,” or “characterized by,” is inclusive or open-ended and does notexclude additional, unrecited elements or method steps. The transitionalphrase “consisting of” excludes any element, step, or ingredient notspecified in the claim. The transitional phrase “consisting essentiallyof” limits the scope of a claim to the specified materials or steps andthose that do not materially affect the basic and novelcharacteristic(s) of the claim. A “consisting essentially of” claimoccupies a middle ground between closed claims that are written in a“consisting of” format and fully open claims that are drafted in a“comprising” format. Absent an indication to the contrary, describing acompound or composition as “consisting essentially of” is not to beconstrued as “comprising,” but is intended to describe the recitedcomponent that includes materials which do not significantly alter thecomposition or method to which the term is applied. For example, afeedstock consisting essentially of a material A can include impuritiestypically present in a commercially produced or commercially availablesample of the recited compound or composition. When a claim includesdifferent features and/or feature classes (for example, a method step,feedstock features, and/or product features, among other possibilities),the transitional terms comprising, consisting essentially of, andconsisting of apply only to the feature class to which it is utilized,and it is possible to have different transitional terms or phrasesutilized with different features within a claim. For example, a methodcan comprise several recited steps (and other non-recited steps), bututilize a catalyst system consisting of specific components;alternatively, consisting essentially of specific components; oralternatively, comprising the specific components and other non-recitedcomponents.

In this disclosure, while systems, processes, and methods are oftendescribed in terms of “comprising” various components, devices, orsteps, the systems, processes, and methods can also “consist essentiallyof” or “consist of” the various components, devices, or steps, unlessstated otherwise.

The term “about” as used herein means that amounts, sizes, formulations,parameters, and other quantities and characteristics are not and neednot be exact, but may be approximate and/or larger or smaller, asdesired, reflecting tolerances, conversion factors, rounding off,measurement error and the like, and other factors known to those ofskill in the art. In general, an amount, size, formulation, parameter orother quantity or characteristic is “about” or “approximate” whether ornot expressly stated to be such. The term “about” also encompassesamounts that differ due to different equilibrium conditions for acomposition resulting from a particular initial mixture. Whether or notmodified by the term “about,” the claims include equivalents to thequantities. The term “about” may mean within 10% of the reportednumerical value, alternatively within 5% of the reported numericalvalue.

Unless indicated otherwise, when a range of any type is disclosed orclaimed, for example a range of the number of carbon atoms, molarratios, temperatures, and the like, it is intended to disclose or claimindividually each possible number that such a range could reasonablyencompass, including any sub-ranges encompassed therein. For example,when describing a range of the number of carbon atoms, each possibleindividual integral number and ranges between integral numbers of atomsthat the range includes are encompassed therein. Thus, by disclosing aC₁ to C₁₀ alkyl group or an alkyl group having from 1 to 10 carbon atomsor “up to” 10 carbon atoms, Applicants' intent is to recite that thealkyl group can have 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms, andthese methods of describing such a group are interchangeable. Whendescribing a range of measurements such as molar ratios, every possiblenumber that such a range could reasonably encompass can, for example,refer to values within the range with one significant digit more than ispresent in the end points of a range. In this example, a molar ratiobetween 1.03:1 and 1.12:1 includes individually molar ratios of 1.03:1,1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1, 1.10:1, 1.11:1, and1.12:1. Applicants' intent is that these two methods of describing therange are interchangeable. Moreover, when a range of values is disclosedor claimed, which Applicants intent to reflect individually eachpossible number that such a range could reasonably encompass, Applicantsalso intend for the disclosure of a range to reflect, and beinterchangeable with, disclosing any and all sub-ranges and combinationsof sub-ranges encompassed therein. In this aspect, Applicants'disclosure of a C₁ to C₁₀ alkyl group is intended to literally encompassa C₁ to C₆ alkyl, a C₄ to C₈ alkyl, a C₂ to C₇ alkyl, a combination of aC₁ to C₃ and a C₅ to C₇ alkyl, and so forth. When describing a range inwhich the end points of the range have different numbers of significantdigits, for example, a molar ratio from 1:1 to 1.2:1, every possiblenumber that such a range could reasonably encompass can, for example,refer to values within the range with one significant digit more than ispresent in the end point of a range having the greatest number ofsignificant digits, in this case 1.2:1. In this example, a molar ratiofrom 1:1 to 1.2:1 includes individually molar ratios of 1.01, 1.02,1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14,1.15, 1.16, 1.17, 1.18, 1.19, and 1.20, all relative to 1, and any andall sub-ranges and combinations of sub-ranges encompassed therein.Accordingly, Applicants reserve the right to proviso out or exclude anyindividual members of any such group, including any sub-ranges orcombinations of sub-ranges within the group, if for any reasonApplicants choose to claim less than the full measure of the disclosure,for example, to account for a reference that Applicants are unaware ofat the time of the filing of the application.

For the purpose of any U.S. national stage filing from this application,all publications and patents mentioned in this disclosure areincorporated herein by reference in their entireties, for the purpose ofdescribing and disclosing the constructs and methodologies described inthose publications, which might be used in connection with the methodsof this disclosure. Any publications and patents discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the inventors are not entitled to antedate such disclosure byvirtue of prior disclosure.

In any application before the United States Patent and Trademark Office,the Abstract of this application is provided for the purpose ofsatisfying the requirements of 37 C.F.R. § 1.72 and the purpose statedin 37 C.F.R. § 1.72(b) “to enable the United States Patent and TrademarkOffice and the public generally to determine quickly from a cursoryinspection the nature and gist of the technical disclosure.” Therefore,the Abstract of this application is not intended to be used to construethe scope of the claims or to limit the scope of the subject matter thatis disclosed herein. Moreover, any headings that can be employed hereinare also not intended to be used to construe the scope of the claims orto limit the scope of the subject matter that is disclosed herein. Anyuse of the past tense to describe an example otherwise indicated asconstructive or prophetic is not intended to reflect that theconstructive or prophetic example has actually been carried out.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R₁, and an upper limit,R_(u), is disclosed, any number falling within the range is specificallydisclosed. In particular, the following numbers within the range arespecifically disclosed: R=R₁+k·(R_(u)−R₁), wherein k is a variableranging from 1 percent to 100 percent with a 1 percent increment, i.e.,k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . . 50percent, 51 percent, 52 percent . . . 95 percent, 96 percent, 97percent, 98 percent, 99 percent, or 100 percent. Moreover, any numericalrange defined by two R numbers as defined in the above is alsospecifically disclosed. Use of the term “optionally” with respect to anyelement of a claim means that the element is required, or alternatively,the element is not required, both alternatives being within the scope ofthe claim.

What is claimed is:
 1. A method comprising: contacting, in an oligomerization reactor, ethylene and an oligomerization catalyst to yield an oligomerization reactor effluent comprising 1-hexene; recovering 1-hexene from the oligomerization reactor effluent; and contacting, in an aromatization reactor, the 1-hexene recovered from the oligomerization reactor effluent with an aromatization catalyst to yield an aromatization reactor effluent comprising benzene.
 2. The method of claim 1, further comprising: cracking ethane, propane, butane, pentane, naphtha, or mixtures thereof in a steam cracker to yield a cracker effluent comprising ethylene; and flowing ethylene recovered from the cracker effluent to the oligomerization reactor.
 3. The method of claim 2, further comprising: recovering light hydrocarbons from the cracker effluent; and using the light hydrocarbons recovered from the cracker effluent for cooling for an oligomerization process containing the oligomerization reactor or for an aromatization process containing the aromatization reactor.
 4. The method of claim 2, further comprising: recovering steam from the steam cracker; and using the steam recovered from the steam cracker in an oligomerization process containing the oligomerization reactor.
 5. The method of claim 2, further comprising: flowing ethylene recovered from the cracker effluent to an alkylation reactor; flowing benzene recovered from the aromatization reactor effluent to the alkylation reactor; and contacting, in the alkylation reactor, the ethylene recovered from the cracker effluent and the benzene recovered from the aromatization reactor effluent with an alkylation catalyst to yield an alkylation reactor effluent comprising ethylbenzene.
 6. The method of claim 5, further comprising: flowing ethylbenzene recovered from the alkylation reactor effluent to a dehydrogenation reactor; and contacting, in the dehydrogenation reactor, ethylbenzene with a dehydrogenation catalyst to yield a dehydrogenation reactor effluent comprising styrene.
 7. The method of claim 1, further comprising: flowing at least a portion of 1-hexene recovered from the oligomerization reactor effluent to a hydrogenation reactor; contacting, in the hydrogenation reactor, the at least a portion of 1-hexene with a hydrogenation catalyst to yield a hydrogenation reactor effluent comprising hexanes; recovering hexanes from the hydrogenation reactor effluent; and contacting, in the aromatization reactor, hexanes recovered from the hydrogenation reactor effluent with the aromatization catalyst to yield the aromatization reactor effluent comprising benzene.
 8. The method of claim 1, wherein the contacting ethylene and an oligomerization catalyst is performed in a presence of a diluent selected from the group consisting of isobutane, cyclohexane, methylcyclohexane, n-alkanes, branched alkanes, iso-paraffin solvents, 2,2,4-trimethylpentane, and combinations thereof.
 9. The method of claim 1, wherein the 1-hexene is recovered from the oligomerization reactor effluent by washing to remove catalyst and fractionation to remove diluent.
 10. The method of claim 1, wherein a conversion of 1-hexene to benzene is greater than about 70 wt. % based on a total amount of 1-hexene fed to the aromatization reactor, wherein a selectivity of 1-hexene to benzene is greater than about 75 wt. % based on a total weight of 1-hexene converted in the aromatization reactor.
 11. The method of claim 1, further comprising: contacting, in a hydrogenation reactor, benzene recovered from the aromatization reactor effluent with a hydrogenation catalyst to yield hydrogenation reactor effluent comprising cyclohexane; recovering cyclohexane from the hydrogenation reactor effluent; and recycling cyclohexane recovered from the hydrogenation reactor effluent to the oligomerization reactor.
 12. The method of claim 1, further comprising: recovering a lower purity 1-hexene stream from the oligomerization reactor effluent; recovering a higher purity 1-hexene stream from the lower purity 1-hexene stream; and flowing a portion of the lower purity 1-hexene stream to a hydrogenation reactor.
 13. The method of claim 1, wherein a sulfur removal system is not used in flowing 1-hexene recovered from the oligomerization reactor effluent to the aromatization reactor.
 14. The method of claim 1, wherein the contacting ethylene and an oligomerization catalyst is performed in a presence of a diluent recovered from the aromatization reactor effluent, wherein the diluent is selected from a raffinate, benzene, toluene, xylene, branched alkanes, or a combination thereof.
 15. The method of claim 1, wherein the oligomerization reactor effluent further comprises heavy hydrocarbons having greater than 8 carbon atoms, the method further comprising: flowing the heavy hydrocarbons recovered from the oligomerization reactor effluent to a steam cracker; and cracking the heavy hydrocarbons in the steam cracker.
 16. The method of claim 1, further comprising: flowing a raffinate recovered from the aromatization reactor effluent to a steam cracker; and cracking the raffinate in the steam cracker.
 17. The method of claim 1, wherein the oligomerization reactor effluent further comprises a heavy hydrocarbon having greater than 8 carbon atoms, the method further comprising: blending the heavy hydrocarbon, a raffinate obtained from the aromatization reactor effluent, or both the heavy hydrocarbon and the raffinate into a motor fuel stream.
 18. The method of claim 1, further comprising: flowing hydrogen and light hydrocarbons having less than 6 carbon atoms recovered from the aromatization reactor effluent to a demethanizer, a depropanizer, or both a demethanizer and a depropanizer.
 19. A system comprising: an oligomerization reactor configured to contact ethylene with an oligomerization catalyst to yield an oligomerization reactor effluent comprising 1-hexene; and an aromatization reactor configured to contact 1-hexene recovered from the oligomerization reactor effluent with an aromatization catalyst to yield an aromatization reactor effluent comprising benzene.
 20. A system comprising: an oligomerization reactor configured to contact ethylene with an oligomerization catalyst to yield an oligomerization reactor effluent comprising 1-hexene; a hydrogenation reactor configured to contact 1-hexene recovered from the oligomerization reactor effluent with a hydrogenation catalyst to yield an aromatization feed comprising hexane; and an aromatization reactor configured to contact the aromatization feed with an aromatization catalyst to yield an aromatization reactor effluent comprising benzene. 